U.S. patent number 10,689,415 [Application Number 15/957,343] was granted by the patent office on 2020-06-23 for conjugates of rgd peptides and (bacterio)chlorophyll photosensitizers.
This patent grant is currently assigned to YEDA RESEARCH AND DEVELOPMENT CO. LTD.. The grantee listed for this patent is YEDA RESEARCH AND DEVELOPMENT COMPANY LTD.. Invention is credited to Alexander Brandis, Doron Eren, Karin Neimann, Efrat Rubinstein, Yoram Salomon, Avigdor Scherz.
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United States Patent |
10,689,415 |
Scherz , et al. |
June 23, 2020 |
Conjugates of RGD peptides and (bacterio)chlorophyll
photosensitizers
Abstract
Conjugates of porphyrin, chlorophyll and bacteriochlorophyll
photosensitizers with RGD-containing peptides or RGD
peptidomimetics are provided that are useful for photodynamic
therapy (PDT), particularly vascular-targeted PDT (VTP), of tumors
and nonneoplastic vascular diseases such as age-related macular
degeneration, and for diagnosis of tumors by different
techniques.
Inventors: |
Scherz; Avigdor (Rehovot,
IL), Salomon; Yoram (Rehovot, IL),
Rubinstein; Efrat (Rehovot, IL), Brandis;
Alexander (Rehovot, IL), Eren; Doron (Rehovot,
IL), Neimann; Karin (Rehovot, IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
YEDA RESEARCH AND DEVELOPMENT COMPANY LTD. |
Rehovot |
N/A |
IL |
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Assignee: |
YEDA RESEARCH AND DEVELOPMENT CO.
LTD. (Rehovot, IL)
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Family
ID: |
47175057 |
Appl.
No.: |
15/957,343 |
Filed: |
April 19, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180305405 A1 |
Oct 25, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13447825 |
Apr 16, 2012 |
9957293 |
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11843996 |
Aug 23, 2007 |
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60839409 |
Aug 23, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07K
5/123 (20130101); C07K 7/06 (20130101); A61P
35/00 (20180101); C07K 5/0817 (20130101); A61K
51/088 (20130101); A61K 51/082 (20130101); C07K
5/126 (20130101); G01N 33/57426 (20130101); C07K
5/10 (20130101); C07K 7/64 (20130101); A61K
41/0071 (20130101); A61K 47/64 (20170801); A61P
35/04 (20180101); A61K 49/0036 (20130101); A61K
41/00 (20130101); G01N 2333/96411 (20130101) |
Current International
Class: |
A61K
51/00 (20060101); C07K 7/06 (20060101); C07K
7/64 (20060101); C07K 5/10 (20060101); C07K
5/09 (20060101); A61K 47/64 (20170101); C07K
5/12 (20060101); A61M 36/14 (20060101); G01N
33/574 (20060101); A61K 41/00 (20200101); A61K
51/08 (20060101); A61K 49/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1998/10795 |
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Mar 1998 |
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WO |
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01/97860 |
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Dec 2001 |
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WO |
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WO-2004045492 |
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Jun 2004 |
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WO |
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Other References
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Enhances the Efficacy of Cancer Drugs" Science 328:1031-1036
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permeability and retention (EPR) and the mechanism of
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by applicant .
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and Polymer-Peptide Conjugates" J Nucl Med, 46:1552-1560 (2005).
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targeting of imaging and therapeutic agents to necrotic domains in
breast tumors" Breast Cancer Research 12:R29, pp. 1-18 (2010).
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Tumor Targeting and Angiogenesis Imaging with Improved
Biokinetics," J Nucl Med 42:326-336 (2001). cited by applicant
.
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therapeutics and imaging agents to the tumour vasculature," Drug
Resistance Updates 8:381-402 (2005). cited by applicant .
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cited by applicant.
|
Primary Examiner: Hartley; Michael G.
Assistant Examiner: Perreira; Melissa J
Attorney, Agent or Firm: Browdy and Neimark, PLLC
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a division of application Ser. No.
13/447,825, filed Apr. 16, 2012, now U.S. Pat. No. 9,957,293.
Application Ser. No. 13/447,825 was a continuation-in-part of
application Ser. No. 11/843,996, filed Aug. 23, 2007, now
abandoned, the entire contents of which are hereby incorporated by
reference. Application Ser. No. 11/843,996 claimed the benefit of
provisional application No. 60/839,409, filed Aug. 23, 2006, the
entire contents of which are also hereby incorporated herein by
reference.
The Sequence Listing in ASCII text file format of 2,895 bytes in
size, created on Apr. 18, 2018, with the file name
"2018-04-19sequenceListing_SCHERZ5C.txt," filed in the U.S. Patent
and Trademark Office on Apr. 19, 2018, is hereby incorporated
herein by reference.
Claims
The invention claimed is:
1. A method for tumor diagnosis or visualization of organs,
comprising: (a) administering to a subject suspected of having a
tumor a conjugate of at least one RGD-containing peptide or
RGD-peptidomimetic and a water soluble chlorophyll or
bacteriochlorophyll photosensitizer; and (b) subjecting the patient
to diagnosis or visualization of organs, wherein the conjugate of
at least one RGD-containing peptide or RGD-peptidomimetic and a
water soluble chlorophyll or bacteriochlorophyll photosensitizer
has the formula II: ##STR00051## wherein M represents 2H or an atom
selected from the group consisting of Mg, Pd, Pt, Co, Ni, Sn, Sm,
Cu, Zn, Mn, In, Eu, Fe, Au, Al, Gd, Dy, Er, Yb, Lu, Ga, Y, Rh, Ru,
Si, Ge, Cr, Mo, P, Re, Tc, Tl and isotopes thereof; R.sub.1 is
--NH--P, wherein P is a residue of an RGD-containing peptide or an
RGD-peptidomimetic; R'.sub.2 is O--R.sub.8; R.sub.6 is
--NR.sub.9R'.sub.9 or --N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
wherein R.sub.1 and R.sub.6 may together form a ring; R.sub.4 is
--CH.dbd.CR.sub.9R'.sub.9, --CH.dbd.CR.sub.9Hal,
--CH.dbd.CH--CH.sub.2--NR.sub.9R'.sub.9,
--CH.dbd.CH--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--CHO, --CH.dbd.NR.sub.9, --CH.dbd.N.sup.+R.sub.9R'.sub.9A.sup.-,
--CH.sub.2--OR.sub.9, --CH.sub.2--SR.sub.9, --CH.sub.2-Hal,
--CH.sub.2--R.sub.9, --CH.sub.2--NR.sub.9R'.sub.9,
--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--CH.sub.2--CH.sub.2R.sub.9, --CH.sub.2--CH.sub.2Hal,
--CH.sub.2--CH.sub.2OR.sub.9, --CH.sub.2--CH.sub.2SR.sub.9,
--CH.sub.2--CH.sub.2--NR.sub.9R'.sub.9,
--CH.sub.2--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A,
--COCH.sub.3, --C(CH.sub.3).dbd.CR.sub.9R'.sub.9,
--C(CH.sub.3).dbd.CR.sub.9Hal, --C(CH.sub.3).dbd.NR.sub.9,
--CH(CH.sub.3).dbd.N.sup.+R.sub.9R'.sub.9A.sup.-,
--CH(CH.sub.3)-Hal, --CH(CH.sub.3)--OR.sub.9,
--CH(CH.sub.3)--SR.sub.9, --CH(CH.sub.3)--NR.sub.9R'.sub.9,
--CH(CH.sub.3)--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-, or
--C.ident.CR.sub.9; R'.sub.4 is methyl or formyl; R.sub.8, R.sub.9,
R'.sub.9 and R''.sub.9 each independently is: (a) H; (b)
C.sub.1-C.sub.25 hydrocarbyl; (c) C.sub.1-C.sub.25 hydrocarbyl
substituted by one or more functional groups selected from the
group consisting of halogen, nitro, oxo, --OR, --SR, epoxy,
epithio, --NRR', --CONRR', --CONR--NRR', --NHCONRR', --NHCONRNRR',
--COR, --COOR, --OSO.sub.3R, --SO.sub.3R, --SO.sub.2R,
--NHSO.sub.2R, --SO.sub.2NRR', .dbd.N--OR,
--(CH.sub.2).sub.n--CO--NRR', --O--(CH.sub.2).sub.n--OR,
--O--(CH.sub.2).sub.n--O--(CH.sub.2).sub.n--R, --OPO.sub.3RR',
--PO.sub.2HR, and --PO.sub.3RR', wherein R and R' each
independently is H, hydrocarbyl or heterocyclyl, R may further be a
cation, R' may further be a residue of an RGD peptide or RGD
peptidomimetic, or R and R' together with the N atom to which they
are attached form a 5-7 membered saturated ring optionally
containing a further heteroatom selected from O, S and N, wherein
the further N atom may be substituted, and n is 1 to 6; (d)
C.sub.1-C.sub.25 hydrocarbyl substituted by one or more functional
groups selected from the group consisting of positively charged
groups, negatively charged groups, basic groups that are converted
to positively charged groups under physiological conditions, and
acidic groups that are converted to negatively charged groups under
physiological conditions; (e) C.sub.1-C.sub.25 hydrocarbyl
containing one or more heteroatoms and/or one or more carbocyclic
or heterocyclic moieties; (f) C.sub.1-C.sub.25 hydrocarbyl
containing one or more heteroatoms and/or one or more carbocyclic
or heterocyclic moieties and substituted by one or more functional
groups as defined in (c) and (d) above; (g) C.sub.1-C.sub.25
hydrocarbyl substituted by a residue of an amino acid, a peptide, a
protein, a monosaccharide, an oligosaccharide, a polysaccharide, or
a polydentate ligand and its chelating complexes with metals; or
(h) a residue of an amino acid, a peptide, a protein, a
monosaccharide, an oligosaccharide, a polysaccharide, or a
polydentate ligand and its chelating complexes with metals; A.sup.-
is a physiologically acceptable anion; m is 0 or 1; the dotted line
at positions 7-8 represents an optional double bond; and
pharmaceutically acceptable salts and optical isomers thereof;
wherein said RGD containing peptide or RGD peptidomimetic is: (A) a
cyclic RGD-containing peptide selected from the group consisting
of: (i) the pentapeptide cycloRGDfK (SEQ ID NO:1), wherein f
indicates D-Phe; (ii) the nonapeptide herein designated RGD-4C (SEQ
ID NO:2); (iii) the tetrapeptide cycloRGDK (SEQ ID NO:4); (iv) the
pentapeptide cycloRGDf-N(Me)K (SEQ ID NO:7), wherein f indicates
D-Phe; and (v) the pentapeptide cycloRGDyK (SEQ ID NO:8), wherein y
indicates D-Tyr; or (B) a linear RGD-containing peptide selected
from the group consisting of: (i) the hexapeptide GRGDSP (SEQ ID
NO:3); (ii) the heptapeptide GRGDSPK (SEQ ID NO:5), and (iii) the
peptide of sequence (GRGDSP).sub.4K (SEQ ID NO:6); or (C) an
RGD-peptidomimetic selected from the group consisting of
H.sub.2N--C(.dbd.NH)NH--(CH.sub.2).sub.5--CO--NH--CH(CH.sub.2)--(CH.sub.2-
).sub.2--COOH; and
H.sub.2N--C(.dbd.NH)NH--(CH.sub.2).sub.3--CO-piperidine-CONH--CH[(CH.sub.-
2).sub.4]--CH.sub.2--COOH; or (D) an RGD-containing peptide or
RGD-peptidomimetic selected from the group consisting of
--NH-RGD-CO--NH--(CH.sub.2).sub.2--NH--; and
--NH-RGD-CO--NH--(CH.sub.2).sub.3piperazino-(CH.sub.2).sub.3--NH--
comprised within a ring formed by R.sub.1 and R.sub.6.
2. The method according to claim 1, for: (i) tumor diagnosis by
dynamic fluorescence imaging, which comprises: (a) administering to
a subject suspected of having a tumor a conjugate of formula II in
claim 1, wherein M is 2H or a metal selected from the group
consisting of Cu, Pd Gd, Pt, Zn, Al, Eu, Er, and Yb and isotopes
thereof; and (b) irradiating the subject by standard procedures and
measuring the fluorescence of the suspected area, wherein a higher
fluorescence indicates tumor sites; (ii) tumor diagnosis by
radiodiagnostic technique, which comprises: (a) administering to a
subject suspected of having a tumor a conjugate formula II in claim
1, wherein M is a radioisotope selected from the group consisting
of .sup.64Cu, .sup.67Cu, .sup.99mTc, .sup.67Ga, .sup.201Tl,
.sup.195Pt, .sup.60Co, .sup.111In and .sup.51Cr; and (b) scanning
the subject in an imaging scanner and measuring the radiation level
of the suspected area, wherein an enhanced radiation indicates
tumor sites; or (iii) molecular magnetic resonance imaging (MRI)
method for tumor diagnosis comprising the steps of: (a) subjecting
a patient suspected of having a tumor to magnetic resonance imaging
and generating a magnetic resonance (MR) image of the target region
of interest within the patient's body; (b) administering to said
patient a conjugate of formula II in claim 1, wherein M is a
paramagnetic metal selected from the group consisting of Mn.sup.3+,
Cu.sup.2+, Fe.sup.3+, Eu.sup.3+, Gd.sup.3+ and Dy.sup.3+; (c)
irradiating the target region of interest within the patient's body
with the appropriate sensitizing radiation; (d) generating at least
one MR image of the target region of interest during and/or after
irradiation; and (e) processing and analyzing the data to diagnose
the presence or absence of a tumor.
3. The method according to claim 2, wherein the tumor diagnosis is
by radiodiagnostic technique, wherein said imaging scanner is
positron emission tomography (PET) and M is .sup.64Cu or .sup.67Cu,
or single photon emission tomography (SPET) and M is a radioisotope
selected from the group consisting of .sup.99mTc, .sup.67Ga,
.sup.195Pt, .sup.111In, .sup.51Cr and .sup.60Co; and wherein said
tumor is a primary tumor or a metastasis from melanoma, colon,
breast, lung, prostate, brain or head and neck cancer.
4. A method for tumor therapy comprising administering to an
individual in need a conjugate of at least one RGD-containing
peptide or RGD-peptidomimetic and a water soluble chlorophyll or
bacteriochlorophyll photosensitizer, said method being: (i) tumor
photodynamic therapy, which comprises: (a) administering the
conjugate to an individual in need; and (b) irradiating the local
of the tumor; or (ii) tumor radiotherapy, which comprises
administering the conjugate to an individual in need, wherein M is
a radioisotope selected from the group consisting of .sup.103Pd,
.sup.195Pt, .sup.105Rh, .sup.106Rh, .sup.188Re, .sup.177Lu,
.sup.164Er, .sup.117mSn, .sup.153Sm, .sup.90Y, .sup.67Cu and
.sup.32P; wherein the conjugate of at least one RGD-containing
peptide or RGD-peptidomimetic and a water soluble chlorophyll or
bacteriochlorophyll photosensitizer has the formula II:
##STR00052## wherein M represents 2H or an atom selected from the
group consisting of Mg, Pd, Pt, Co, Ni, Sn, Sm, Cu, Zn, Mn, In, Eu,
Fe, Au, Al, Gd, Dy, Er, Yb, Lu, Ga, Y, Rh, Ru, Si, ge, Cr, Mo, P,
Re, Tc, Tl and isotopes thereof; R.sub.1 is --NH--P, wherein P is a
residue of an RGD-containing peptide or an RGD-peptidomimetic;
R'.sub.2 is O--R.sub.8; R.sub.6 is --NR.sub.9R'.sub.9 or
--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-, wherein R.sub.1 and
R.sub.6 may together form a ring comprising an RGD peptide or RGD
peptidomimetic residue; R.sub.4 is --CH.dbd.CR.sub.9R'.sub.9,
--CH.dbd.CR.sub.9Hal, --CH.dbd.CH--CH.sub.2--NR.sub.9R'.sub.9,
--CH.dbd.CH--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--CHO, --CH.dbd.NR9, --CH.dbd.N.sup.+R.sub.9R'.sub.9A.sup.-,
--CH.sub.2--OR.sub.9, --CH.sub.2--SR.sub.9, --CH.sub.2-Hal,
--CH.sub.2--R.sub.9, --CH.sub.2--NR.sub.9R'.sub.9,
--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--CH.sub.2--CH.sub.2R.sub.9, --CH.sub.2--CH.sub.2Hal,
--CH.sub.2--CH.sub.2OR.sub.9, --CH.sub.2--CH.sub.2SR.sub.9,
--CH.sub.2--CH.sub.2--NR.sub.9R'.sub.9,
--CH.sub.2--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A,
--COCH.sub.3, --C(CH.sub.3).dbd.CR.sub.9R'.sub.9,
--C(CH.sub.3).dbd.CR.sub.9Hal, --C(CH.sub.3).dbd.NR.sub.9,
--CH(CH.sub.3).dbd.N.sup.+R.sub.9R'.sub.9A.sup.-,
--CH(CH.sub.3)-Hal, --CH(CH.sub.3)--OR.sub.9,
--CH(CH.sub.3)--SR.sub.9, --CH(CH.sub.3)--NR.sub.9R'.sub.9,
--CH(CH.sub.3)--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-, or
--C.ident.CR.sub.9; R'.sub.4 is methyl or formyl; R.sub.8, R.sub.9,
R'.sub.9 and R''.sub.9 each independently is: (a) H; (b)
C.sub.1-C.sub.25 hydrocarbyl; (c) C.sub.1-C.sub.25 hydrocarbyl
substituted by one or more functional groups selected from the
group consisting of halogen, nitro, oxo, --OR, --SR, epoxy,
epithio, --NRR', --CONRR', --CONR--NRR', --NHCONRR', --NHCONRNRR',
--COR, COOR, --OSO.sub.3R, --SO.sub.3R, --SO.sub.2R, --NHSO.sub.2R,
--SO.sub.2NRR', .dbd.N--OR, --(CH.sub.2).sub.n--CO--NRR',
--O--(CH.sub.2).sub.n--OR,
--O--(CH.sub.2).sub.n--O--(CH.sub.2).sub.n--R, --OPO.sub.3RR',
--PO.sub.2HR, and --PO.sub.3RR', wherein R and R' each
independently is H, hydrocarbyl or heterocyclyl, R may further be a
cation, R' may further be a residue of an RGD peptide or RGD
peptidomimetic, or R and R' together with the N atom to which they
are attached form a 5-7 membered saturated ring optionally
containing a further heteroatom selected from O, S and N, wherein
the further N atom may be substituted, and n is 1 to 6; (d)
C.sub.1-C.sub.25 hydrocarbyl substituted by one or more functional
groups selected from the group consisting of positively charged
groups, negatively charged groups, basic groups that are converted
to positively charged groups under physiological conditions, and
acidic groups that are converted to negatively charged groups under
physiological conditions; (e) C.sub.1-C.sub.25 hydrocarbyl
containing one or more heteroatoms and/or one or more carbocyclic
or heterocyclic moieties; (f) C.sub.1-C.sub.25 hydrocarbyl
containing one or more heteroatoms and/or one or more carbocyclic
or heterocyclic moieties and substituted by one or more functional
groups as defined in (c) and (d) above; (g) C.sub.1-C.sub.25
hydrocarbyl substituted by a residue of an amino acid, a peptide, a
protein, a monosaccharide, an oligosaccharide, a polysaccharide, or
a polydentate ligand and its chelating complexes with metals; or
(h) a residue of an amino acid, a peptide, a protein, a
monosaccharide, an oligosaccharide, a polysaccharide, or a
polydentate ligand and its chelating complexes with metals; A.sup.-
is a physiologically acceptable anion; m is 0 or 1; the dotted line
at positions 7-8 represents an optional double bond; and
pharmaceutically acceptable salts and optical isomers thereof;
wherein said RGD-containing peptide or RGD peptidomimetic is: (A) a
cyclic RGD-containing peptide selected from the group consisting
of: (i) the pentapeptide cycloRGDfK (SEQ ID NO:1), wherein f
indicates D-Phe; (ii) the nonapeptide herein designated RGD-4C (SEQ
ID NO:2); (iii) the tetrapeptide cycloRGDK (SEQ ID NO:4); (iv) the
pentapeptide cycloRGDf-N(Me)K (SEQ ID NO:7), wherein f indicates
D-Phe; and (v) the pentapeptide cycloRGDyK (SEQ ID NO:8), wherein y
indicates D-Tyr; or (B) a linear RGD-containing peptide selected
from the group consisting of: (i) the hexapeptide GRGDSP (SEQ ID
NO:3); (ii) the heptapeptide GRGDSPK (SEQ ID NO:5), and (iii) the
peptide of sequence (GRGDSP).sub.4K (SEQ ID NO:6); or (C) an
RGD-peptidomimetic selected from the group consisting of
H.sub.2N--C(.dbd.NH)NH--(CH.sub.2).sub.5--CO--NH--CH(CH.sub.2)--(CH.sub.2-
).sub.2--COOH; and
H.sub.2N--C(.dbd.NH)NH--(CH.sub.2).sub.3--CO--piperidine--CONH--CH[(CH.su-
b.2).sub.4]--CH.sub.2--COOH; or (D) an RGD-containing peptide or
RGD-peptidomimetic selected from the group consisting of
--NH--RGD--CO--NH--(CH.sub.2).sub.2--NH--; and
--NH--RGD--CO--NH--(CH.sub.2).sub.3piperazino--(CH.sub.2).sub.3--NH--
comprised within a ring formed by R.sub.1 and R.sub.6.
5. The method according to claim 4, wherein said tumor is a primary
tumor or a metastasis from melanoma, colon, breast, lung, prostate,
brain or head and neck cancer.
6. The method according to claim 1, wherein: (i) any of the
C.sub.1-C.sub.25 hydrocarbyl groups is a C.sub.1-C.sub.25 alkyl,
alkenyl or alkynyl; (ii) said negatively charged group is selected
from the group consisting of --COO.sup.-, --COS.sup.-,
--SO.sub.3.sup.-, and --PO.sub.3.sup.2-; (iii) said acidic group
that is converted to a negatively charged group at the
physiological pH is selected from the group consisting of --COOH,
--COSH, --SO.sub.3H, an --PO.sub.3H.sub.2, or a salt thereof; (iv)
said positively charged group is: (a) a cation derived from a
N-containing group selected from the group consisting of
--N.sup.+(RR'R''), --(R)N--N.sup.+(RR'R''), O.rarw.N.sup.+(RR')--,
>C.dbd.N.sup.+(RR'), --C(.dbd.NR)--N.sup.+RR'R'' and
--(R)N--C(.dbd.NR)--N.sup.+RR'R''; (b) a cation derived from a
heteroaromatic compound containing one or more N atoms and
optionally O or S atoms, selected from the group consisting of
pyrazolium, imidazolium, oxazolium, thiazolium, pyridinium,
quinolinium, isoquinolinium, pyrimidinium, 1,2,4-triazinium,
1,3,5-triazinium and purinium, said cation being an end group or a
group located within an alkyl chain; or (c) an onium group selected
from the group consisting of --O.sup.+(RR'), --S.sup.+(RR'),
--Se.sup.+(RR'), --Te.sup.+(RR'), --P.sup.+(RR'R''),
--As.sup.+(RR'R''), --Sb.sup.+(RR'R''), and --Bi.sup.+(RR'R''); (v)
said basic group that is converted to a positively charged group
under physiological conditions is selected from the group
consisting of --NRR', --C(.dbd.NR)--NR'R'', --NR--NR'R'',
--(R)N--C(.dbd.NR)--NR'R'', O.rarw.NR--, and >C.dbd.NR, or the
basic group is a N-containing heteroaromatic radical selected from
the group consisting of pyrazolyl, imidazolyl, oxazolyl, thiazolyl,
pyridyl, quinolinyl, isoquinolinyl, pyrimidyl, 1,2,4-triazinyl,
1,3,5-triazinyl and purinyl, wherein said basic group is an end
group or a group located within an alkyl chain; wherein R, R' and
R'' each independently is H, optionally substituted hydrocarbyl or
heterocyclyl, or two of R, R' and R'' together with the N atom to
which they are attached form a 3-7 membered saturated ring,
optionally containing one or more heteroatoms selected from O, S or
N, and optionally further substituted at the additional N atom,
said 3-7 membered saturated ring being selected from the group
consisting of aziridine, pyrrolidine, piperidine, morpholine,
thiomorpholine, azepine and piperazine optionally substituted at
the additional N atom by C.sub.1-C.sub.6 alkyl optionally
substituted by halo, hydroxyl or amino.
7. The method of claim 1, wherein the photosensitizer in the
conjugate is selected from the group consisting of: (i) a
bacteriochlorophyll of the formula II, wherein M is 2H or a metal
selected from the group consisting of Pd, Mn and Cu; and (ii) a
chlorophyll of the formula II, wherein M is 2H or a metal selected
from the group consisting of Pd, Mn and Cu.
8. The method of claim 1, wherein M is a radioisotope selected from
the group consisting of .sup.99mTc, .sup.67Ga, .sup.195Pt,
.sup.111In, .sup.51Cr, .sup.60Co, .sup.103Pd, .sup.195Pt,
.sup.105Rh, .sup.106Rh, .sup.188Re, .sup.177Lu, .sup.164Er,
.sup.117mSn, .sup.153Sm, .sup.90Y, .sup.64Cu, .sup.67Cu and
.sup.32P.
9. The method of claim 1, wherein the photosensitizer in the
conjugate is a bacteriochlorophyll of formula II, wherein R.sub.4
at position 3 is acetyl, R.sub.4 at position 8 is ethyl, and
R'.sub.4 is methyl, or a chlorophyll of formula II, wherein R.sub.4
at position 3 is vinyl, R.sub.4 at position 8 is ethyl, and
R'.sub.4 is methyl.
10. The method of claim 9, wherein the photosensitizer is selected
from the group consisting of: (i) a chlorophyll or
bacteriochlorophyll of the formula II, wherein R.sub.6 is
--NR.sub.9R'.sub.9, R.sub.9 is H and R'.sub.9 is C.sub.1-C.sub.10
alkyl substituted by (a) the acidic group SO.sub.3H or an alkaline
salt thereof; (b) a basic group --NH--(CH.sub.2).sub.2-6--NRR'
wherein each of R and R' independently is H, C.sub.1-C.sub.6 alkyl
optionally substituted by NH.sub.2, or R and R' together with the N
atom form a 5-6 membered saturated ring, optionally containing an O
or N atom and optionally further substituted at the additional N
atom by --(CH.sub.2).sub.2-6--NH.sub.2; (c) one or more OH; or (d)
a polydentate ligand selected from the group consisting of EDTA,
DTPA and DOTA, and their chelating complexes with metals; and (ii)
a chlorophyll or bacteriochlorophyll of formula II, wherein R.sub.1
and R.sub.6 together form a cyclic ring comprising an RGD peptide
or RGD peptidomimetic.
11. The method of claim 10, wherein in the conjugate (i) R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3K,
--NH--(CH.sub.2).sub.3--SO.sub.3K,
--NH--(CH.sub.2).sub.3--NH--(CH.sub.2).sub.3--NH.sub.2,
--NH--(CH.sub.2).sub.2-1-morpholino,
--NH--(CH.sub.2).sub.3-piperazino-(CH.sub.2).sub.3--NH.sub.2,
--NH--CH.sub.2--CH(OH)--CH.sub.2(OH), or
--NH--(CH.sub.2).sub.3--NH-DTPA or its chelating complex with Gd;
or (ii) R.sub.1 and R.sub.6 together form a cyclic ring comprising
--NH-RGD-CO--NH--(CH.sub.2).sub.2--NH-- or
--NH-RGD-CO--NH--(CH.sub.2).sub.2-piperazino-(CH.sub.2).sub.2--NH--.
12. The method of claim 1, wherein the photosensitizer is selected
from the group consisting of: (a) a bacteriochlorophyll of the
formula II wherein m is 0; R.sub.1 is NH--P, wherein P is the
residue of an RGD-containing peptide or RGD peptidomimetic linked
directly to the NH-- or via a spacer; R'.sub.2 is methoxy; R.sub.4
at position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; and wherein (i) M is Pd, Mn, Cu or 2H and R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3.sup.-Me.sup.+ or
--NH--(CH.sub.2).sub.3--SO.sub.3Me.sup.+, wherein Me.sup.+ is
Na.sup.+ or K.sup.+; (ii) M is Pd or 2H and R.sub.6 is
--NH--CH.sub.2--CH(OH)--CH.sub.2--OH; (iii) M is 2H and R.sub.6 is
--NH--(CH.sub.2).sub.3--NH--(CH.sub.2).sub.3--NH.sub.2, (iv) M is
2H and R.sub.6 is --NH--(CH.sub.2).sub.2-morpholino; or (v) M is 2H
and R.sub.6 is
--NH--(CH.sub.2).sub.3-piperazino-(CH.sub.2).sub.3--NH.sub.2; and
(b) a chlorophyll of the formula II wherein M is selected from the
group consisting of Mn, Cu and 2H; R.sub.1 is NH--P, wherein P is
the residue of an RGD-containing peptide or RGD peptidomimetic
linked directly to the NH-- or via a spacer; R.sub.4 at position 3
is vinyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3Me.sup.+, wherein
Me.sup.+ is Na.sup.+ or K.sup.+.
13. The method of claim 1, wherein the conjugate is selected from
the group consisting of: palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[4-(methyl-5-(6-guanidino-hexanoyla-
mino)-pentanoic acid)]amide potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[7-amido-3-[[1-(4-guanidino-butyryl-
)-piperidine-3-carbonyl]-amino]-heptanoic acid] potassium salt,
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo(2-RGD-amido-N-ethyl)diamide,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo(2-RGD-amido-N-ethyl)diamide, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo{3-[4-(3-aminopropyl-DGR-amido)-piperazin-1-yl]-pr-
opyl}diamide, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(RGD-4C)amide potassium salt,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, manganese(III)
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, copper(II)
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(GRGDSP)amide potassium salt,
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(GRGDSPK)amide potassium
salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[(GRGDSP).sub.4K]amide
potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDf-N(Me)K)amide
potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)-17.sup.3-N-[4-heptanedioic acid
bis-(cycloRGDyK-amido)]amide potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin-13.sup.1-(2,3-d-
ihydroxypropyl)amide-17.sup.3-(cycloRGDfK)amide,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(3-DTPA-amido-N-propyl)amide-17.sup.3-(cycloRGDfK)amide,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(3-Gd-DTPA-amido-N-propyl)amide-17.sup.3-(cycloRGDfK)amide,
3.sup.1,3.sup.2-didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, manganese(III) 3.sup.1,3.sup.2-didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, and copper(II) 3.sup.1,3.sup.2-didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt.
14. The method according to claim 1, wherein the conjugate is
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt or 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt.
15. The method according to claim 4, wherein: (i) any of the
C.sub.1-C.sub.25 hydrocarbyl groups is a C.sub.1-C.sub.25 alkyl,
alkenyl or alkynyl; (ii) said negatively charged group is selected
from the group consisting of --COO.sup.-, --COS.sup.-,
--SO.sub.3.sup.-, and --PO.sub.3.sup.2-; (iii) said acidic group
that is converted to a negatively charged group at the
physiological pH is selected from the group consisting of --COOH,
--COSH, --SO.sub.3H, and --PO.sub.3H.sub.2 or a salt thereof; (iv)
said positively charged group is: (a) a cation derived from a
N-containing group selected from the group consisting of
--N.sup.+(RR'R''), --(R)N--N.sup.+(RR'R''), O.rarw.N.sup.+(RR')--,
>C.dbd.N.sup.+(RR'), --C(.dbd.NR)--N.sup.+RR'R'' and
--(R)N--C(.dbd.NR)--N.sup.+RR'R''; (b) a cation derived from a
heteroaromatic compound containing one or more N atoms and
optionally O or S atoms, selected from the group consisting of
pyrazolium, imidazolium, oxazolium, thiazolium, pyridinium,
quinolinium, isoquinolinium, pyrimidinium, 1,2,4-triazinium,
1,3,5-triazinium and purinium, said cation being an end group or a
group located within an alkyl chain; or (c) an onium group selected
from the group consisting of --O.sup.+(RR'), --S.sup.+(RR'),
--Se.sup.+(RR'), --Te.sup.+(RR'), --P.sup.+(RR'R''),
--As.sup.+(RR'R''), --Sb.sub.+(RR'R''), and --Bi.sup.+(RR'R''); (v)
said basic group that is converted to a positively charged group
under physiological conditions is selected from the group
consisting of --NRR', --C(.dbd.NR)--NR'R'', --NR--NR'R'',
--(R)N--C(.dbd.NR)--NR'R'', O.rarw.NR--, and >C.dbd.NR, or the
basic group is a N-containing heteroaromatic radical selected from
the group consisting of pyrazolyl, imidazolyl, oxazolyl, thiazolyl,
pyridyl, quinolinyl, isoquinolinyl, pyrimidyl, 1,2,4-triazinyl,
1,3,5-triazinyl and purinyl, wherein said basic group is an end
group or a group located within an alkyl chain; wherein R, R' and
R'' each independently is H, optionally substituted hydrocarbyl or
heterocyclyl, or two of R, R' and R'' together with the N atom to
which they are attached form a 3-7 membered saturated ring,
optionally containing one or more heteroatoms selected from O, S or
N, and optionally further substituted at the additional N atom,
said 3-7 membered saturated ring being selected from the group
consisting of aziridine, pyrrolidine, piperidine, morpholine,
thiomorpholine, azepine and piperazine optionally substituted at
the additional N atom by C.sub.1-C.sub.6 alkyl optionally
substituted by halo, hydroxyl or amino.
16. The method of claim 4, wherein the photosensitizer in the
conjugate is selected from the group consisting of: (i) a
bacteriochlorophyll of the formula II, wherein M is 2H or a metal
selected from the group consisting of Pd, Mn and Cu; and (ii) a
chlorophyll of the formula II, wherein M is 2H or a metal selected
from the group consisting of Pd, Mn and Cu.
17. The method of claim 4, wherein M is a radioisotope selected
from the group consisting of .sup.99mTc, .sup.67Ga, .sup.195Pt,
.sup.111In, .sup.51Cr, .sup.60Co .sup.103Pd, .sup.195Pt,
.sup.105Rh, .sup.106Rh, .sup.188Re, .sup.177Lu, .sup.164Er,
.sup.117mSn, .sup.153Sm, .sup.90Y, .sup.64Cu, .sup.67Cu, and
.sup.32P.
18. The method of claim 4, wherein the photosensitizer in the
conjugate is a bacteriochlorophyll of formula II, wherein R.sub.4
at position 3 is acetyl, R.sub.4 at position 8 is ethyl, and
R'.sub.4 is methyl, or a chlorophyll of formula II, wherein R.sub.4
at position 3 is vinyl, R.sub.4 at position 8 is ethyl, and
R'.sub.4 is methyl.
19. The method of claim 9, wherein the photosensitizer is selected
from the group consisting of: (i) a chlorophyll or
bacteriochlorophyll of the formula II, wherein R.sub.6 is
--NR.sub.9R'.sub.9, R.sub.9 is H and R'.sub.9 is C.sub.1-C.sub.10
alkyl substituted by (a) the acidic group SO.sub.3H or an alkaline
salt thereof; (b) a basic group --NH--(CH.sub.2).sub.2-6--NRR'
wherein each of R and R' independently is H, C.sub.1-C.sub.6 alkyl
optionally substituted by NH.sub.2, or R and R' together with the N
atom form a 5-6 membered saturated ring, optionally containing an O
or N atom and optionally further substituted at the additional N
atom by --(CH.sub.2).sub.2-6--NH.sub.2; (c) one or more OH; or (d)
a polydentate ligand selected from the group consisting of EDTA,
DTPA and DOTA, and their chelating complexes with metals; and (ii)
a chlorophyll or bacteriochlorophyll of formula II, wherein R.sub.1
and R.sub.6 together form a cyclic ring comprising an RGD peptide
or RGD peptidomimetic.
20. The method of claim 19, wherein in the conjugate (i) R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3K,
--NH--(CH.sub.2).sub.3--SO.sub.3K,
--NH--(CH.sub.2).sub.3--NH--(CH.sub.2).sub.3--NH.sub.2,
--NH--(CH.sub.2).sub.2-1-morpholino,
--NH--(CH.sub.2).sub.3-piperazino-(CH.sub.2).sub.3--NH.sub.2,
--NH--CH.sub.2--CH(OH)--CH.sub.2(OH), or
--NH--(CH.sub.2).sub.3--NH-DTPA or its chelating complex with Gd;
or (ii) R.sub.1 and R.sub.6 together form a cyclic ring comprising
--NH-RGD-CO--NH--(CH.sub.2).sub.2--NH-- or
--NH-RGD-CO--NH--(CH.sub.2).sub.2-piperazino-(CH.sub.2).sub.2--NH--.
21. The method of claim 4, wherein the photosensitizer is selected
from the group consisting of: (a) a bacteriochlorophyll of the
formula II wherein m is 0; R.sub.1 is NH--P, wherein P is the
residue of an RGD-containing peptide or RGD peptidomimetic linked
directly to the NH-- or via a spacer; R'.sub.2 is methoxy; R.sub.4
at position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; and wherein (i) M is Pd, Mn, Cu or 2H and R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3Me.sup.+ or
--NH--(CH.sub.2).sub.3--SO.sub.3Me.sup.+, wherein Me.sup.+ is
Na.sup.+ or K.sup.+; (ii) M is Pd or 2H and R.sub.6 is
--NH--CH.sub.2--CH(OH)--CH.sub.2--OH; (iii) M is 2H and R.sub.6 is
--NH--(CH.sub.2).sub.3--NH--(CH.sub.2).sub.3--NH.sub.2; (iv) M is
2H and R.sub.6 is --NH--(CH.sub.2).sub.2-morpholino; or (v) M is 2H
and R.sub.6 is
--NH--(CH.sub.2).sub.3-piperazino-(CH.sub.2).sub.3--NH.sub.2; and
(b) a chlorophyll of the formula II wherein M is selected from the
group consisting of Mn, Cu and 2H; R.sub.1 is NH--P, wherein P is
the residue of an RGD-containing peptide or RGD peptidomimetic
linked directly to the NH-- or via a spacer; R.sub.4 at position 3
is vinyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3Me.sup.+, wherein
Me.sup.+ is Na.sup.+ or K.sup.+.
22. The method of claim 4, wherein the conjugate is selected from
the group consisting of: palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[4-(methyl-5-(6-guanidino-hexanoyla-
mino)-pentanoic acid)]amide potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[7-amido-3-[[1-(4-guanidino-butyryl-
)-piperidine-3-carbonyl]-amino]-heptanoic acid]potassium salt,
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo(2-RGD-amido-N-ethyl)diamide,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo(2-RGD-amido-N-ethyl)diamide, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo
{3-[4-(3-aminopropyl-DGR-amido)-piperazin-1-yl]-propyl}diamide,
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(RGD-4C)amide potassium salt,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, manganese(III)
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, copper(II)
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(GRGDSP)amide potassium salt,
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(GRGDSPK)amide potassium
salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[(GRGDSP)4K]amide potassium
salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDf-N(Me)K)amide
potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)-17.sup.3-N-[4-heptanedioic acid
bis-(cycloRGDyK-amido)]amide potassium salt, palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin-13.sup.1-(2,3-d-
ihydroxypropyl)amide-17.sup.3-(cycloRGDfK)amide,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(3-DTPA-amido-N-propyl)amide-17.sup.3-(cycloRGDfK)amide,
3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(3-Gd-DTPA-amido-N-propyl)amide-17.sup.3-(cycloRGDfK)amide,
3.sup.1,3.sup.2-didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, manganese(III) 3.sup.1,3.sup.2-didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt, and copper(II) 3.sup.1,3.sup.2-didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt.
23. The method according to claim 4, wherein the conjugate is
palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt or 3.sup.1-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt.
Description
FIELD OF THE INVENTION
The present invention relates to photosensitizers and in particular
to novel conjugates of porphyrin, chlorophyll and
bacteriochlorophyll derivatives with peptides containing the RGD
motif or with RGD peptidomimetics, to their preparation and their
use in methods of in-vivo photodynamic therapy and diagnosis of
tumors and different vascular diseases such as age-related macular
degeneration.
DEFINITIONS AND ABBREVIATIONS
AMD: age-related macular degeneration; Bchl a: bacteriochlorophyll
a: pentacyclic 7,8,17,18-tetrahydroporphyrin with a 5.sup.th
isocyclic ring, a central Mg atom, a phytyl or geranylgeranyl group
at position 17.sup.3, a COOCH.sub.3 group at position 13.sup.2, an
H atom at position 13.sup.2, methyl groups at positions 2, 7, 12,
18, an acetyl group at position 3, and an ethyl group at position
8, herein compound 1; Bphe: bacteriopheophytin a (Bchl in which the
central Mg is replaced by two H atoms); Bpheid:
bacteriopheophorbide a (the C-17.sup.2-free carboxylic acid derived
from Bphe without the central metal atom); Chl: chlorophyll; EC:
endothelial cells; ECM: extracellular matrix; NIR: near-infrared;
Pd-Bpheid: Pd-bacteriopheophorbide a; PDT: photodynamic therapy;
RGD-4C: the cyclic nonapeptide CDCRGDCFC-NH.sub.2;
Rhodobacteriochlorin: tetracyclic 7,8,17,18-tetrahydroporphyrin
having a --CH.sub.2CH.sub.2COOH group at position 17, a --COOH at
position 13, methyl groups at positions 2, 7, 12, 8, and ethyl
groups at positions 3 and 8; ROS: reactive oxygen species; VTI:
vascular-targeted imaging; VTP: vascular-targeted PDT.
IUPAC numbering of the bacteriochlorophyll derivatives is used
throughout the specification. Using this nomenclature, the natural
bacteriochlorophylls carry two carboxylic acid esters at positions
13.sup.2 and 17.sup.2, however they are esterified at positions
13.sup.3 and 17.sup.3.
BACKGROUND OF THE INVENTION
Photodynamic therapy (PDT) is a non-surgical treatment of tumors in
which non-toxic drugs and non-hazardous photosensitizing
irradiation are combined to generate cytotoxic reactive oxygen
species in situ. This technique is more selective than the commonly
used tumor chemotherapy and radiotherapy.
PDT of tumors involves the combination of administered
photosensitizer and local light delivery, both innocuous agents by
themselves, but in the presence of molecular oxygen they are
capable of producing cytotoxic reactive oxygen species (ROS) that
can inactivate cells. Being a binary treatment modality, PDT allows
for greater specificity and has the potential of being more
selective, yet not less destructive, when compared with commonly
used chemotherapy or radiotherapy (Dougherty et al., 1998; Bonnett
et al., 1999; Kessel and Dougherty, 1999; Mazon, 1999; Hahn and
Glatstein, 1999).
Porphyrins have been employed as the primary photosensitizing
agents in clinics. Optimal tissue penetration by light apparently
occurs between 650-800 nm. Porfimer sodium (Photofrin.RTM., a
trademark of Axcan Pharma Inc.), the world's first approved
photodynamic therapy agent, which is obtained from
hematoporphyrin-IX by treatment with acids and has received FDA
approval for treatment of esophageal and endobronchial non-small
cell lung cancers, is a complex and inseparable mixture of
monomers, dimers, and higher oligomers.
Large amounts of work have been devoted to the synthesis of single
pure compounds--so-called "second generation" sensitizers--which
absorb at long wavelength, have well established structures and
exhibit better differentiation between their retention in tumor
cells and their retention in skin or other normal tissues. In order
to optimize the performance of the porphyrin drugs in therapeutics
and diagnostics, several porphyrin derivatives have been proposed
in which, for example, there is a central metal atom (other than
Mg) complexed to the four pyrrole rings, and/or the peripheral
substituents of the pyrrole rings are modified and/or the
macrocycle is dihydrogenated to chlorophyll derivatives (chlorins)
or tetrahydrogenated to bacteriochlorophyll derivatives
(bacteriochlorins).
Due to their intense absorption in favorable spectral regions
(650-850 nm) and their ready degradation after treatment,
chlorophyll (Chl) and bacteriochlorophyll (BChl) derivatives have
been identified as excellent sensitizers for PDT of tumors and to
have superior properties in comparison to porphyrins.
Bacteriochlorophylls are of potential advantage compared to the
chlorophylls because they show intense near-infrared bands, i.e.,
at considerably longer wavelengths than chlorophyll
derivatives.
Tumor Vascular Targeting
Targeting photodynamic reagents for destruction of the tumor
vasculature, as opposed to the tumor cells themselves, may offer
therapeutic advantages since tumor-cell growth and development
critically depend on continuous oxygen and nutrient supply
(Ruoslahti, 2002). Such vascular damage may include thrombus
formation and further restrict tumor blood perfusion (Huang et al.,
1997). Furthermore, targeting the tumor vascular endothelial cell
(EC) layer is expected to circumvent the poor penetration of tumor
stroma by the therapeutic macromolecules (Huang et al., 1997;
Burrows and Thorpe 1994). Although tumor blood vessels might be
affected by the tumor microenvironment and acquire a tumor
associated "signature", they are not malignant and less likely to
develop drug resistance. Furthermore, when a targeted antivascular
agent is also active against the tumor cells, additional gains in
efficacy can be expected. Thus, by combining antivascular
properties with antitumor cytotoxic activities in one drug, its
efficacy can be expected to increase and, consequently, decrease
the required effective cytotoxic dose. In addition to ECs, tumor
cells have also been shown in one case to comprise part of the
luminal surface mosaic of the tumor blood vessels (Ruoslahti, 2002;
Chang at al, 2000). Consequently these tumor cells are thought to
be directly exposed to the blood and freely interact with
therapeutic macromolecules that otherwise are unable to cross the
endothelial barrier.
Selective vascular targeting can rely on the differential
susceptibility and consequent response to therapeutic agents of
tumor and normal blood vessels. Alternatively, differential
endocytosis may promote selective uptake of cytotoxic or other
therapeutic agents. Recent studies have suggested organ/tissue
specific properties for vascular ECs (Ruoslahti, 2002). The blood
vessels in different tissues are likely to express tissue specific
endothelial markers that are mostly unknown. Pathological processes
such as inflammation, ischemia and malignancy can also impose their
signature on the respective vasculature (Ruoslahti, 2002; Ruoslahti
and Rajotte, 2000; Ruoslahti, 2000; Rajotte et al., 1998; Arap et
al., 1998). The biochemical features that characterize blood
vessels in tumors may include angiogenesis-related molecules such
as certain integrins. The integrins .alpha..sub.v.beta..sub.3,
.alpha..sub.v.beta..sub.5 and .alpha..sub.5.beta..sub.1 have been
identified in expression patterns typical for angiogenic vascular
ECs associated with tumors, wounds, inflammatory tissue, and during
vascular remodeling (Brooks et al, 1994a; Brooks et al, 1994b;
Brooks et al, 1995; Elceiri and Cheresh, 1999). Endothelial-cell
growth factor receptors, proteases, peptidases, cell surface
proteoglycans and extracellular matrix (ECM) components have also
been described (Ruoslahti, 2000). This rich repertoire of
heterogenic molecules and processes may provide new opportunities
for targeted delivery of therapies.
Different strategies have been pursued to achieve this goal.
Circulating peptides, peptidomimetics or antibodies that target
specific sites in the vasculature are attractive as carriers for
therapeutics and diagnostic agents offering theoretical advantages
over such conjugates that directly target tumor cells, mostly
situated beyond physiological barriers such as the blood vessel
wall.
Chaleix et al., 2003, disclose the synthesis of RGD-porphyrin
conjugates as potential candidates for PDT application, in which
the unmetalated porphyrin macrocycle is substituted at each of the
positions 10,15,20 by 4-methylphenyl or acetylatedglucosyloxyphenyl
and at position 5 by a residue of a linear RGD-containing peptide
linked to the macrocycle via a spacer arm.
Selective uptake of RGD-containing peptides by endothelial and
tumor cells via .alpha..sub.v.beta..sub.3 and
.alpha..sub.v.beta..sub.5 integrins
The arginine-glycine-aspartic acid Arg-Gly-Asp (RGD) motif of ECM
components, like fibronectin (Pierschbacher and Ruoslahti, 1984)
and vitronectin, binds to integrins (Ruoslahti and Pierschbacher,
1987; D'Souza S E et al., 1991; Joshi et al, 1993; Koivunen et al.,
1994). Integrin-mediated adhesion leads to intracellular signaling
events that regulate cell survival, proliferation, and migration.
Some 25 integrins are known, and at least eight of them bind the
RGD motif as the primary recognition sequence in their ligands.
Data obtained by phage display methods (Pasqualini and Ruoslahti,
1996) screening for RGD-containing peptides, have shown their
selective binding to endothelial lining of tumor blood vessels
(Ruoslahti, 1996; Pasqualini et al., 1997). Because the expression
of integrins is reported to be high on activated, but more
restricted on quiescent, ECs, small synthetic RGD-containing
peptides have been proposed as antagonists impairing the growth of
vascular endothelial and tumor cells. RGD peptides also retard
signal transmission, affect cell migration and induce tumor cell
regression or apoptosis (Su et al., 2002). RGD-analogues are used
in tumor imaging (Haubner et al., 2001), anti-angiogenesis
approaches (Kawaguchi et al., 2001; Pasqualini et al., 2000), and
in tumor targeting of radionucleotides (van Hagen et al., 2000) and
chemotherapeutic drugs (Arap et al., 1998; Zitzmann et al.,
2002).
Integrins are also expressed on cancer cells and therefore play an
important role in the invasion, metastasis, proliferation and
apoptosis of cancer cells. Metastasis invasion of tumor cells into
preferred organs may represent cell-homing phenomena that depend on
the adhesive interaction between the tumor cells and organ-specific
endothelial markers (Ruoslahti and Rajotte, 2000). By binding to
integrin of either endothelial or tumor cells, RGD peptides are
capable of modulating in vivo cell traffic by inhibition of tumor
cell-ECM and tumor cell-EC attachments, which are obligatory for
metastatic processes. Several studies have indicated that
RGD-containing compounds can interfere with tumor cell metastatic
processes in vitro (Goligorsky et al., 1998; Romanov and Goligorsky
1999) and in vivo (Saiki et al., 1989; Hardan et al., 1993).
Peptides that are specific for individual integrins are of
considerable interest and of possible medical significance. The
.alpha..sub.v.beta..sub.3 integrin was the first integrin shown to
be associated with tumor angiogenesis. RGD peptides that
specifically block the .alpha.v.beta.3 integrin show promise as
inhibitors of tumor and retinal angiogenesis, of osteoporosis and
in targeting drugs to tumor vasculature (Assa-Munt et al., 2001).
Coupling of the anticancer drug doxorubicin or a pro-apoptotic
peptide to an .alpha.v.beta.3 integrin-binding RGD peptide yields
compounds that are more active and less toxic than unmodified drugs
when tested against xenograft tumors in mice (Ruoslahti, 2000; Arap
et al., 1998; Arap et al., 2002; Ellerby et al., 1999).
U.S. Pat. No. 6,576,239, EP 0927045 B1 and WO 98/010795 (all of The
Burnham Institute, Inventors: E. Ruoslahti and R. Pasqualini)
disclose a conjugate comprising a tumor homing peptide comprising
the amino acid sequence RGD or NGR, said tumor homing peptide
linked to a therapeutic or diagnostic moiety, provided said moiety
is not a phage particle. The therapeutic moiety may be a cytotoxic
agent or a cancer chemotherapeutic agent such as doxorubicin. The
conjugate selectively homes to angiogenic vasculature upon in vivo
administration. The tumor homing peptide may be a peptide of up to
20 or 30 amino acids or of 50 to 100 amino acids in length, linear
or cyclic. One preferred peptide is the cyclic nonapeptide,
CDCRGDCFC or
H-Cys*-Asp-Cys*-Arg-Gly-Asp-Cys*-Phe-Cys*--NH.sub.2.
Selective Vascular Response Induced in Tumors by Photodynamic
Therapy (PD7)
Application of novel bacteriochlorophyll (Bchl) derivatives as
sensitizers in PDT has been reported by our group in recent years
in the scientific literature (Zilberstein et al., 2001; Schreiber
et al., 2002; Gross et al., 1997; Zilberstein et al., 1997;
Rosenbach-Belkin et al., 1996; Gross et al., 2003a; Koudinova et
al., 2003; Preise et al., 2003; Gross et al., 2003b) and in the
patent publications U.S. Pat. Nos. 5,726,169, 5,650,292, 5,955,585,
6,147,195, 6,740,637, 6,333,319, 6,569,846, 7,045,117, DE 41 21
876, EP 1 246 826, WO 2004/045492, WO 2005/120573. The spectra,
photophysics, and photochemistry of Bchl derivatives have made them
optimal light-harvesting molecules with clear advantages over other
sensitizers presently used in PDT. These Bchl derivatives are
mostly polar and remain in the circulation for a very short time
with practically no extravasations into other tissues (Brandis et
al., 2003). Therefore, these compounds are good candidates for
vascular-targeted PDT that relies on short (5-10 min) temporal
intravascular encounter with light and higher susceptibility of the
tumor vessels to the PDT-generated cytotoxic ROS.
Recent studies performed by our group showed that primary
photosensitization is intravascular with rapid development of
ischemic occlusions and stasis within the illumination period. This
process also induces photochemically induced lipid peroxidation
(LPO) and early EC death that is primarily confined to the tumor
vasculature (Gross et al., 2003a; Koudinova et al., 2003). Due to
light independent progression of free radical chain reactions along
with developing hypoxia, LPO and cell death spread beyond the
vascular compartment to cover the entire tumor interstitium until
complete necrosis of the tumor is attained around 24 hours post
PDT. Hence, the primary action of PDT blocks blood supply and
induces hypoxia that initiates, in a secondary manner, a series of
molecular and pathophysiological events that culminate with tumor
eradication.
Mitochondria, lysosomes, plasma membrane, and nuclei of cells have
been evaluated as potential PDT targets. Since most PDT sensitizers
do not accumulate in cell nuclei, PDT has a generally low potential
of causing DNA damage, mutations, and carcinogenesis. Hydrophilic
sensitizers are likely to be taken up by pinocytosis and/or
endocytosis and therefore become localized in lysosomes or
endosomes. Light exposure will then permeabilize the lysosomes so
that sensitizers and hydrolytic enzymes are released into the
cytosol (Dougherty et al., 1998).
PDT damage to plasma membrane can be observed within minutes after
light exposure. This type of damage is manifested as swelling,
shedding of vesicles containing plasma membrane marker enzymes,
cytosolic enzymes and lysosomal enzymes, reduction of active
transport, depolarization of plasma membrane, inhibition of the
activities of plasma membrane enzymes, changes in intracellular
Ca.sup.2+, up- and down-regulation of surface antigens, LPO that
may lead to protein crosslinking, and damage to multidrug
transporters (Dougherty et al., 1998).
Reports that PDT could rapidly induce apoptosis, both in vitro and
in vivo, have provided insight into the nature of the photokilling
mechanisms. Insight into the mechanism of apoptosis after PDT has
perhaps been provided by reports that indicate an association
between mitochondrial photodamage and apoptotic responses. Recent
studies performed by our group showed that the Bchl based
photosensitizers induce the activation of the apoptotic pathway.
However, apoptosis is probably not the cause for cell death, since
inhibiting the apoptotic pathways did not rescue the cells (Mazor
et al. 2003, unpublished).
Reference is made to the following patents and patent applications
of the applicants of the present application, the contents of all
these patents and patent applications being hereby incorporated by
reference in their entirety as if fully disclosed herein: U.S. Pat.
Nos. 5,726,169, 5,650,292, 5,955,585, 6,147,195, 6,740,637,
6,333,319, 6,569,846, 7,045,117, DE 41 21 876, EP 1 246 826, WO
2004/045492, WO 2005/120573.
SUMMARY OF THE INVENTION
The present invention relates to a conjugate of a RGD-containing
peptide or RGD peptidomimetic and a photosensitizer selected from
the group consisting of porphyrin, chlorophyll and
bacteriochlorophyll, excluding the conjugates wherein the
photosensitizer is unmetalated porphyrin substituted at each of the
positions 10,15,20 by 4-methylphenyl or acetylated
glucosyloxyphenyl and at position 5 by a residue of a linear
RGD-containing peptide linked to the porphyrin macrocycle via a
spacer arm.
In one embodiment, the photosensitizer is a porphyrin, preferably a
tetraarylporphyrin. In another embodiment, the photosensitizer is a
chlorophyll or bacteriochlorophyll, preferably of the formulas I,
II and III herein.
The invention further provides a diagnostic, therapeutic or
radiotherapeutic composition for visualization, PDT therapy or
radiotherapy of tissues or organs comprising an effective amount of
a photosensitizer-RGD peptide conjugate of the invention and a
pharmaceutically acceptable carrier.
The conjugates of the invention can be used in methods for tumor
diagnosis using different diagnostic techniques and in methods of
photodynamic therapy of tumors and vascular diseases and in tumor
radiotherapy.
BRIEF DESCRIPTION OF THE FIGURES
The present patent or application file contains at least one
drawing executed in color. Copies of this patent or patent
application publication with color drawings will be provided by the
Office upon request and payment of the necessary fee.
FIGS. 1A-1C show characterization spectra of conjugate 11. FIG. 1A:
Mass spectrometry measurement. FIG. 1B: Spectrophotometry analysis.
FIG. 1C: HPLC results after synthesis (conjugate 11 is peak number
3).
FIGS. 2A-2B show characterization spectra of conjugate 9. FIG. 2A:
Electronic spectrum in acetone. FIG. 2B: Mass spectrum: ESI-MS (+)
679 (M), 702 (M+Na) m/z.
FIGS. 3A-3B show purification and characterization of Eu-RGD-4C.
FIG. 3A: Chromatography of Eu-RGD-4C (a single pick). FIG. 3B: Mass
spectrometry analysis (MW of
isothiocyanatophenyl-DTPA-Eu-RGD-4C=1498, arrow).
FIG. 4 shows the results of a receptor-binding assay. The specific
binding activity of free Eu-RGD-4C to the integrin receptor was
measured using H5V cells in the absence (total binding) or presence
of 1 .mu.M RGD-4C (non-specific binding).
FIG. 5 shows Scatchard analysis of bound (B) and free (F) Eu-RGD-4C
based on the results of the receptor-binding assay described in
FIG. 4.
FIG. 6 shows results of a solid phase receptor assay measuring
Eu-RGD-4C binding to isolated .alpha..sub.v.beta..sub.3 integrin
receptor. Time-resolved fluorometry was used for fluorescence
determination.
FIGS. 7A-7B show the effect of RGD-4C on H5V endothelial cells
detachment. The morphological changes of the cells were documented
using light microscopy. 5% of rounded cells (n=200) after
incubation in the absence (FIG. 7A) and 99% in the presence of
RGD-4C (FIG. 7B). After replacement of the medium with a fresh one
and incubation for 3 h at 37.degree. C., the % of rounded cells
(n=200) in the absence and in the presence of RGD-4C were 6% and
8%, respectively (not shown).
FIG. 8 shows the effect of RGD-4C on HUVEC detachment. The
morphological changes of the cells were documented using light
microscopy. The upper panels a-e represent the phase contrast
microscopy of cell detachment in the presence of increasing
concentrations of RGD-4C (a: control; b: 25 .mu.M; c: 50 .mu.M; d:
100 .mu.M; e: 200 .mu.M). The lower panels represent the recovery
of the cells 24 h after replacement of the medium with a fresh
one.
FIG. 9 shows the cellular uptake and localization of conjugate 24
in H5V endothelial cells as depicted in a trans photograph (a), a
fluorescence image (b) (excitation filter: 520 nm; emission filter:
780 nm) and a merge of the photograph and image (c).
FIG. 10 is a series of fluorescence images showing the cellular
uptake and localization of conjugate 24 and compound 8 in H5V
endothelial cells measured 20 min (upper panels) or 2.5 hours
(lower panels) after incubation with the compounds in a medium
containing 10% or 75% FCS (excitation filter: 520 nm; emission
filter: 780 nm). (a) 8, 10% FCS; (b) 24, 10% FCS; (c) 8, 75% FCS;
(d) 24, 75% FCS.
FIGS. 11A-11C are a series of graphs showing the biodistribution of
conjugate 24, i.v. injected into CD1 nude male mice with tumor
xenografts of rat C6 glioma (11A; each time point represents 6
mice), mouse CT26luc colon carcinoma (11B; each time point
represents 2 mice), and mouse 4T1luc carcinoma of the breast (11C;
each time point represents 3 mice), sacrificed at the indicated
times. Pd concentrations in different organs were determined by
ICP-MS. The boxes present time-windows most suitable for PDT and
imaging measurements.
FIG. 12 shows biodistribution of compound 8, i.v. injected (tail
vein) into CD1-nude male mice with tumor xenografts of rat C6
glioma, sacrificed at the indicated times. Pd concentrations were
determined by ICP-MS.
FIG. 13 shows the biodistribution of Cu-conjugate 15 in mice
bearing MDA-MB-231 breast tumor. The animals were sacrificed at
selected time points. Cu concentrations are shown at selected time
point, after the subtraction of time 0, as an average value from
three animals.
FIGS. 14A-14B are graphs showing the biodistribution of conjugate
42 (that contains the RAD motif), i.v. injected into CD1 nude male
mice with tumor grafts of mouse CT26luc colon carcinoma, sacrificed
at the indicated times. Pd concentrations in different organs were
determined by ICP-MS. FIG. 14A ICP-MS results for conjugate 42.
Each time point represents 2 mice. FIG. 14B shows the same results
with focus on specific organs of interest (blood, tumor, liver,
kidneys and muscle) compared to the results obtained for RGD
conjugate 24 (see FIGS. 11A-11C).
FIG. 15 shows a comparison of whole-body NIR fluorescence imaging
after administration of the compound 8 (upper panels) or of
conjugate 24. The given images illustrate the fluorescence of a
mouse bearing rat C6 glioma xenograft on the back of the right
posterior limb (a) 4 hours, (b) 24 hours, (c) 48 hours and (d) 72
hours post injection of 200 nmol dose of conjugate 24 or compound
8. Tumors are indicated by arrows and all images are normalized to
the same scale.
FIGS. 16A-16C are a photograph (16A), a fluorescence image (16B)
and a luminescence image (luciferase+luciferin; 16C) of a mouse
bearing, on the right anterior limb, a subcutaneous xenograft of
CT26luc colon cancer (transfected with luciferase) 24 hr after the
injection of 200 nmol dose of conjugate 24. The fluorescence and
luminescence images were acquired using IVIS system.
FIGS. 17A-17C show photographs (17A) and fluorescence (17B) and
bioluminescence (17C) images of two mice bearing subcutaneous
grafts of mouse 4T1luc mammary gland cancer (transfected with
luciferase) on the right anterior limb, 24 hr after the injection
of 200 nmol dose of conjugate 24.
FIG. 18 shows the fluorescence imaging of a mouse bearing ovarian
carcinoma MLS xenograft, taken: (B) 8 (left panel) and (C) 14
(right panel) hours after i.v. injection of conjugate 31. The
fluorescence and luminescence images were acquired using IVIS
system.
FIG. 19 shows fluorescence images of two mice bearing rat C6 glioma
xenograft 24 hours after the administration of 140 nmol of
conjugate 24 alone (left mouse), or one hour after injection of 8.5
.mu.mol of cycloRGDfK peptide (right mouse). Each mouse was
documented from above (upper panel, left) and from aside (upper
panel, right). Zoom in photographs are also shown (lower panel).
The circles on the fluorescence images indicate the location of the
xenografted rat C6 glioma tumor.
FIG. 20 shows black & white photographs (upper panels) and
fluorescence images (lower panels) of CD-1 nude male mice bearing
CT26luc xenografts on the back of the posterior limb, 24 hours
after the administration of RGD conjugate 24 (panels a,c) or RAD
conjugate 42 (panels b,d). Tumors are indicated by arrows and all
images are normalized to the same scale. The fluorescence images
were acquired using IVIS system.
FIG. 21 shows black & white photographs (upper panels) and
fluorescence images (lower panels) of mice bearing (a) OVCAR 8, (b)
CT26luc, (c) MLS, and (d) 4T1luc xenografts on the back of the
posterior limb, 24 hours after the administration of c conjugate
24. Tumors are indicated by arrows and all images are normalized to
the same scale.
FIG. 22 shows a photograph (upper image, taken using digital
camera) and a fluorescence image (lower image) from conjugate 24
localization in lung metastasis of 4T1luc breast cancer tumor in
BALB/c female mouse, 24 hr after i.v. injection of conjugate 24 (15
mg/kg). The NIR fluorescence signal originated from localization of
conjugate 24 taken using Imaging System Xenogen IVIS.RTM. 100.
FIGS. 23A-23I are a series of photographs (a), bioluminescence (b)
and fluorescence (c) images of CT26luc lung metastases in CD-1 nude
male mice 24 hours (A,B), 9 hours (C,D), 4 hours (E,F) after the
i.v. injection of conjugate 24 (15 mg/kg). Images G,H are of
CT26luc lung metastases in CD-1 nude male mice that were not
injected with the conjugate. Image I is of CD-1 nude male mouse
without lung metastases 24 hours after the i.v. injection of
conjugate 24. The middle image is the bioluminescence signal
originated from the reaction of luciferin with the luciferase
transfected tumor cells. The right image is the NIR fluorescence
signal originated from 24 taken using Xenogen IVIS.RTM. Imaging
System 100. The arrows indicate the lung metastases.
FIG. 24 shows black & white photographs (a), bioluminescence
(b) and fluorescence (c) images of CD-1 nude male mouse bearing
CT26luc primary tumor on the back of its left leg and metastases in
the near lymph node, 24 hours after the i.v. injection of conjugate
24 (15 mg/kg). The middle image is the bioluminescence signal
originated from the reaction of luciferin with the luciferase
transfected tumor cells. The right image is the NIR fluorescence
signal originated from conjugate 24 taken using Xenogen IVIS.RTM.
Imaging System 100. The arrows indicate the lymph node
metastases.
FIGS. 25A-25C show dose-response survival curve of H5V cells
incubated for 90 min at 37.degree. C. with 0-25 .mu.M conjugate 23
or compound 10 in different media conditions: 10% FCS in medium
(FIG. 25A), culture medium DMEM/F12 (FIG. 25B) or 10 .mu.M BSA in
medium (FIG. 25C). Cell survival was determined using Neutral Red
viability assay. The points represent average results of
triplicates.
FIGS. 26A-26D show dose-response survival curves of H5V cells
incubated for 90 min at 37.degree. C. with 0-25 .mu.M compound 10
(FIGS. 16A, 16B) or conjugate 23 (FIGS. 26C, 26D) in the absence or
presence of free cycloRGDfK in excess (100-fold up to 1 mM), in
different media conditions (10% FCS in medium (FIGS. 26A, 27C) or
10 .mu.M BSA in medium (FIGS. 26B, 26D)). Cell survival was
determined using Neutral Red viability assay. The points represent
average results of triplicates.
FIGS. 27A-27B show dose-response survival curves of H5V cells
incubated for 15 min at 37.degree. C. (FIG. 27A) or 4.degree. C.
(FIG. 27B) with 0-20 .mu.M conjugate 23 in 10% FCS in medium in the
absence or presence of excess free cycloRGDfK (100 fold up to 1
mM). Cell survival was determined using Neutral Red viability
assay. The points represent average results of triplicates.
FIG. 28 shows dose-response survival curve of H5V cells incubated
for 2 hours at 37.degree. C. with 0-25 .mu.M conjugate 24 in
culture medium DMEM/F12 with 10% FCS. Cell survival was determined
using Neutral Red viability assay. The points represent average
results of triplicates.
FIG. 29 shows dose-response survival curve of H5V cells incubated
90 min at 37.degree. C. with 0-20 .mu.M conjugate 11 or compound 8
(Pd-MLT) in 10 .mu.M BSA in medium. Cell survival was determined
using Neutral Red viability assay. The points represent average
results of triplicates.
FIGS. 30A-30B show dose-response survival curves of H5V cells
incubated for 90 min at 37.degree. C. with 0-10 .mu.M conjugate 11
(FIG. 30A) or compound 8 (FIG. 30B) in 10 .mu.M BSA in medium in
the absence or presence of excess RGD-4C (1 mM). Cell survival was
determined using Neutral Red viability assay. The points represent
average results of triplicates.
FIGS. 31A-31E are pictures of C6 glioma tumor xenografts treated
with conjugate 24 or compound 8. CD-1 nude male mice bearing C6
glioma xenografts were treated as follows: 31A. conjugate 24 was
i.v. injected 15 mg/kg, 15-min illumination (90 J/cm.sup.2) 8 hours
post injection; upper panels: (a) pre PDT; (b) 2 days post PDT; (c)
3 days post PDT; (d) 4 days post PDT; lower panels: (a) 7 days post
PDT; (b) 9 days post PDT; (c) 14 days post PDT; (d) 18 days post
PDT. 31B. conjugate 24 was i.v. injected 24 mg/kg, 10-min
illumination (60 J/cm.sup.2) 8 hours post injection; a, b, c and d
in upper and lower panels as for 31A. 31C. Dark control--conjugate
24 was i.v. injected without illumination; a) pre PDT, b) 5 days
post PDT. 31D. Light control--illumination without injection of
photosensitizer; a) pre PDT, b) 5 days post PDT. 31E. Unconjugated
photosensitizer control--compound 8 was i.v. injected 9 mg/kg, 10
min illumination (60 J/cm.sup.2) 8 hours post injection, a) pre
PDT, b) 11 days post PDT. Images were taken at indicated time post
PDT.
FIGS. 32A-32F show the therapeutic results of applying 15 mg/kg, 10
min illumination (60 J/cm.sup.2), 8 hours post injection of
conjugate 24 to mice bearing CT26luc tumors. 32A--conjugate 24 was
i.v. injected 15 mg/kg, 10 min illumination (60 J/cm.sup.2) 8 hours
post injection; a) pre PDT, b) 1 day post PDT; (c) 4 days post PDT;
(d) 8 days post PDT; (e) 12 days post PDT; (f) 19 days post PDT.
32B--overlaid images taken after i.p. injection of luciferin to the
mouse described in 32A, using the IVIS system. The first image is
black and white, which gives the photograph of the animal. The
second image is color overlay of the emitted photon data. All
images are normalized to the same scale; (a) pre PDT; (b) 1 day
post PDT; (c) 4 days post PDT; (d) 8 days post PDT.
32C--Bioluminescence signal quantification (photon/sec/cm.sup.2) of
the data shown in 32B. 32D--control with compound 8 alone: the mice
were i.v. injected with compound 8 and illuminated after 8 hours;
(a) pre PDT; (b) 2 days post PDT. 32E--control with mixture of
compound 8 and cycloRGDfK: the mice were i.v. injected with mixture
of compound 8 with cycloRGDfK and illuminated after 8 hours; (a)
pre PDT; (b) 2 days post PDT. 32F--control with cycloRGDfK alone:
the mice were i.v. injected with cycloRGDfK and illuminated after 8
hours; (a) pre PDT; (b) 2 days post PDT. Images were taken at
indicated time post PDT.
FIG. 33 shows the Kaplan-Mayer curve for the protocols indicated in
the Table 5 with asterisk.
FIGS. 34A-34B show the fluorescent mammary cancer MDA-MB-231 RFP
clone 3 (resistant to hygromycin) after 1 sec and 3 sec exposure,
respectively.
FIGS. 35A-35B show two representative examples to local response of
human mammary cancer MDA-MB-231-RFP to PDT. Mice with
MDA-MB-231-RFP xenografts (.about.0.5 cm3) on their backs were i.v.
injected with 7.5 mg/kg of conjugate 13 and illuminated 8 h later
through the mouse skin. 35A--Photographs taken from (a) day 0
(before treatment) and after treatment at (b) 1, (c) 4, (d) 7, (e)
12 and (f) 90 days. By day 4 partial necrosis was seen, by day 7
tumor flattening was observed, after 90 days the wound healed and
the animal was cured. At the right, photographs of the mouse at day
0 and after 90 days. 35B--In vivo whole-body red fluorescence
imaging of CD-1 nude male mice bearing MDA-MB-231-RFP orthotopic
tumor. The photos were taken at the times like in 35A. No signal
was detected 90 days after treatment.
FIG. 36 shows accumulation of conjugate 13 in orthotopic human
breast MDA-MB-231-RFP primary tumor (tumor size .about.1 cm.sup.3).
Images were taken from 15 min to 24 hr post drug injection. Upper
panels--In vivo whole-body red fluorescence imaging of CD-1 nude
female mice bearing MDA-MB-231-RFP orthotopic tumor. Lower
panels--In vivo whole-body NIR fluorescence imaging of conjugate 13
accumulation. The drug shows no specific accumulation in the tumor
during the first 24 hours: (a) 15 min, (b) 1 h, (c) 2 h, (d) 3 h,
(e) 4.5 h, (f) 6 h, (g) 7.5 h, (h) 9 h, (i) 24 h.
FIG. 37 shows accumulation of conjugate 13 in orthotopic human
breast MDA-MB-231-RFP primary tumor (tumor size .about.1 cm.sup.3).
Images were taken from day 1 to 6 post drug injection. Top
panel--In vivo whole-body red fluorescence imaging of CD-1 nude
female mice bearing MDA-MB-231-RFP orthotopic tumor. Bottom
panel--In vivo whole-body NIR fluorescence imaging of conjugate 13
accumulation. The drug shows accumulation in the tumor, reaching
peak concentration specifically in the tumor from day 2 post
injection: (a) 1 h, (b) 9 h, (c) 1 day, (d) 2 days, (e) 3 days, (f)
4 days, (g) 5 days, (h) 6 days, (i) 7 days.
FIGS. 38A-38B present the biodistribution of conjugate 13 and
non-conjugated compound 25 in MDA-MB-231-RFP tumor-bearing CD-1
nude, female mice (n=3 for each time point), that were
intravenously injected with: (A) 15 mg/kg conjugate 13 or, (B) 9
mg/kg compound 25 and sacrificed at the indicated times. Values
represent averaged fluorescence intensities (.+-.standard
deviation),
FIGS. 39A-39B are fluorescence images showing accumulation of
compound 25 in CD-1 nude female mice grafted with an orthotopically
large MDA-MB-231-RFP tumors. Images were taken within few hour
after i.v. injection of 9 mg/kg compound 25 (39A) and accumulation
of 25 was then monitored for up to three days (39B). Upper
panel-near infrared (NIR) fluorescence images indicating compound
25 distribution; lower panel-Red fluorescence images indicating
tumor location.
FIGS. 40A-40C are fluorescence images showing accumulation of
conjugate 13 and compound 25 covalently bound to HSA in large
MDA-MB-231-RFP tumors in CD-1 nude female mice, following i.v.
injection of 0.7 nmol of HSA-conjugate 13 (A) or HSA-compound 25
(B). Images of the tumors were taken at the indicated times
post-injection. Upper panel--near infrared (NIR) fluorescence
images indicating compound distribution; lower panel--red
fluorescence images indicating tumor size and location.
Longitudinal accumulation of conjugate 13 covalently bound to HSA
and compound 25 covalently bound to HSA in large tumors is
presented in graph 40C. Total fluorescence intensity within the
individual tumor boundaries at the indicated times was normalized
per unit area and expressed as photon/(sec.times.cm.sup.2).
DETAILED DESCRIPTION OF THE INVENTION
In a broad aspect, the present invention relates to a conjugate of
a photosensitizer selected from porphyrin, chlorophyll (Chl) and
bacteriochlorophyll (BChl) and an RGD-containing peptide or an RGD
peptidomimetic
It is one object of the present invention to provide conjugates of
photosensitizers that specifically target the sensitizer to the
tumor vasculature. There are some advantages for vascular
photosensitizer targeting over vascular targeting with conventional
chemotherapy. First, during accumulation of a targeted conventional
drug, it is often active, unless it is a prodrug, while the
targeted photosensitizer is not active until locally illuminated.
Second, a targeted conventional drug will bind and act also at
undesirable targets presenting the homing address whereas the
targeted photosensitizer will be activated only at the relevant
illuminated site. Furthermore, PDT with photosensitizers targeted
to the neovascular endothelial signatures in tumor may be
remarkably selective in inducing photodynamic EC injury.
The integrin .alpha..sub.v.beta..sub.3 receptor has been reported
to play an important role in tumor metastasis and angiogenesis,
which involves growth of new blood vessels from preexisting
vasculatures during tumor growth. This integrin may be a viable
marker for tumor growth and spread. Therefore, noninvasive imaging
methods for visual monitoring of integrin .alpha..sub.v.beta..sub.3
expression in real-time provides opportunities for assessing
therapeutic intervention as well as for detection of
metastasis.
Integrins mediate the attachment between a cell and the tissue
surrounding it which may be another cell or the extracellular
matrix (ECM). Integrins bind peptides and proteins which comprise
the RGD motif within. RGD peptides interact with the integrin
receptor sites, which can initiate cell-signaling processes and
influence many different diseases. Thus, the integrin RGD binding
site is an attractive pharmaceutical target. The integrin
.alpha..sub.v.beta..sub.3 has an RGD binding site and peptides
containing the sequence RGD home to, and act as antagonists of,
.alpha..sub.v.beta..sub.3 integrin. Thus, in one preferred
embodiment of the invention, the RGD-containing peptide is an
antagonist of an integrin receptor.
In the bifunctional conjugates of the invention, the homing
property is provided by the RGD-containing peptide while the PDT
effect is provided by the photosensitizer. These conjugates should
be able to target the sensitizer to neovessels of primary solid
tumors and possibly respective metastases for the purpose of
diagnosis and for photodynamic destruction. They can further act as
antiangiogenic agents and initiate apoptotic destruction of
neoendothelial and blood exposed tumor cells.
The terms "RGD-containing peptide" or "RGD peptide" are used herein
interchangeably and mean a peptide containing the RGD sequence,
also referred to as RGD motif. The term "RGD peptidomimetic" as
used herein refers to compounds, particularly, non-peptidic
compounds, that mimic peptides having the RGD motif.
The RGD-containing peptide may be a linear or cyclic peptide
composed of 4-100, preferably 5-50, 5-30, 5-20 or, more preferably,
5-10, amino acid residues. In preferred embodiments, the RGD
peptide is composed of 4, 5, 6, 7, 9 or 25, most preferably 5 amino
acid residues.
As used herein, the term "amino acid" includes the 20 naturally
occurring amino acids as well as non-natural amino acids.
Examples of natural amino acids suitable for the invention include,
but are not limited to, Ala, Arg, Asp, Cys, Gln, Glu, Gly, Ile,
Leu, Lys, Met, Phe, Pro, Ser, Thr, Tyr, and Val.
Examples of non-natural amino acids include, but are not limited
to, 4-aminobutyric acid (Abu), 2-aminoadipic acid, diaminopropionic
(Dap) acid, hydroxylysine, homoserine, homovaline, homoleucine,
norleucine (Nle), norvaline (Nva), ornithine (Orn), TIC,
naphthylalanine (Nal), ring-methylated derivatives of Phe,
halogenated derivatives of Phe or o-methyl-Tyr.
The term "amino acid" herein includes also modified amino acids
such as modifications that occur post-translationally in vivo, for
example, hydroxyproline, phosphoserine and phosphothreonine;
D-modification; N-alkylation, preferably N-methylation, of the
peptide bond; acylation or alkylation of the amino terminal group
or of the free amino group of Lys; esterification or amidation of
the carboxy terminal group or of a free carboxy group of Asp or
Glu; and esterification or etherification of the hydroxyl group of
Ser or Tyr.
The term "amino acid" includes both D- and L-amino acids. Thus, the
peptides used in the conjugates of the invention can be all-D
(except for glycine), all-L or L,D-amino acids. D-modifications as
well as N-alkylation of the peptide bond are most beneficial to
prevent peptide cleavage by enzymes in the organism. In the present
invention, a D-amino acid is indicated by a small letter as for the
D-phenylalanine `f` residue in the peptide cycloRGDfK of SEQ ID
NO:1 used herein.
The present invention includes also cyclic peptides. Peptides can
be cyclized by a variety of methods such as formation of
disulfides, sulfides and, especially, lactam bonds between carboxyl
and amino functions of the N- and C-termini or amino acid side
chains. Cyclization can be obtained by any method known in the art,
for example, through amide bond formation, e.g., by incorporating
Glu, Asp, Lys, Orn, diamino butyric (Dab) acid, diaminopropionic
(Dap) acid at various positions in the chain (--CO--NH or --NH--CO
bonds). Backbone to backbone cyclization can also be obtained
through incorporation of modified amino acids of the formulas
H--N(CH.sub.2).sub.n--COOH)--C(R)H--COOH or
H--N((CH.sub.2).sub.n--NH.sub.2)--C(R)H--COOH, wherein n=1-4, and
further wherein R is any natural or non-natural side chain of an
amino acid.
Cyclization can also be obtained via formation of S--S bonds
through incorporation of two Cys residues. Additional side-chain to
side chain cyclization can be obtained via formation of an
interaction bond of the formula
--(CH.sub.2).sub.n--S--CH.sub.2--CO--, wherein n=1 or 2, which is
possible, for example, through incorporation of Cys or homoCys and
reaction of its free SH group with, e.g., bromoacetylated Lys, Orn,
Dab or Dap.
In some embodiments, the RGD peptides may be those described in
U.S. Pat. No. 6,576,239 and EP 0927045, herein incorporated by
reference in their entirety as if fully disclosed herein.
In one preferred embodiment, the peptide used according to the
invention is the cyclic pentapeptide RGDfK of SEQ ID NO:1, wherein
`f` indicates a D-Phe residue.
In another preferred embodiment, the peptide is the cyclic
nonapeptide CDCRGDCGC of SEQ ID NO:2, herein designated `RGD-4C`,
which contains four cysteine residues forming two disulfide bonds
in the molecule, and is one of the promising peptides with integrin
specificity. This peptide was shown to be a selective and potent
ligand (affinity constant of .about.100 nM) of the
.alpha..sub.v.beta..sub.5 and .alpha..sub.v.beta..sub.3 integrins
(Ruoslahti, 2002; Elceiri and Cheresh, 1999).
The aspartic acid residue of the RGD motif is highly susceptible to
chemical degradation, leading to the loss of biological activity,
and this degradation could be prevented by cyclization via
disulfide linkage (Bogdanowich-Knipp et al., 1999). Along with
improving stability, double cyclic peptides show higher potency
compared to single disulphide-bridge and linear peptides in
inhibiting the attachment of vitronectin to cells. The high
activity of double cyclic RGD peptide is likely to be due to an
appropriately restrained conformation not only of the RGD motif but
also of the flanking amino acids. The number and nature of residues
flanking the RGD sequence in synthetic peptides have a significant
influence on how that sequence is recognized by individual integrin
receptors (Koivunen et al., 1995; Pierschbacher and Ruoslahti,
1987). An aromatic residue may be particularly significant in
making favorable contacts in the binding site of integrin (Koivunen
et al., 1995). Cyclic RGD peptides targeted for
.alpha..sub.v.beta..sub.3 internalize by an integrin independent
fluid-phase endocytosis pathway that does not alter the number of
functional integrin receptors on the cell surface. Additionally,
cyclic RGD peptides remain or degrade in the lysosome, in a process
that reaches saturation after 15 minutes, and only a small portion
can leave the lysosome and reach the cell cytoplasm. This explains
why cyclic RGD peptides are found in the cell cytoplasm only after
a certain period of time (48 to 72 hours) (Hart et al., 1994;
Castel et al., 2001).
In other preferred embodiments, the RGD peptide is selected from
the cyclic peptides: (i) tetrapeptide cycloRGDK (SEQ ID NO:4),
pentapeptide cycloRGDf-n(Me)K (SEQ ID NO:7), wherein f indicates
D-Phe and the peptide bond between f and K is methylated; and
pentapeptide cycloRGDyK (SEQ ID NO:8), wherein y indicates
D-Tyr.
In another embodiment, the RGD-containing peptide is linear and may
be selected from the hexapeptide GRGDSP (SEQ ID NO:3), the
heptapeptide GRGDSPK (SEQ ID NO:5), and the 25-mer (GRGDSP).sub.4K
(SEQ ID NO:7)
In one embodiment of the invention, the RGD peptide is linked
directly to the photosensitizer porphyrin, chlorophyll or
bacteriochlorophyll macrocycle via a functional group in its
periphery, for example, COOH, forming an amide CO--NH.sub.2 group
with the amino terminal group or a free amino group of the RGD
peptide.
In another embodiment, the RGD peptide is linked to the
photosensitizer macrocycle via a spacer arm/bridging group such as,
but not limited to, a C.sub.1-C.sub.25 hydrocarbylene, preferably a
C.sub.1-C.sub.10 alkylene or phenylene, substituted by an end
functional group such as OH, COOH, SO.sub.3H, COSH or NH.sub.2,
thus forming an ether, ester, amide, thioamide or sulfonamide
group.
In some embodiments, the photosensitizer is conjugated to a RGd
peptidomimetic.
In one preferred embodiment the RGD peptidomimetic is a
non-peptidic compound comprising a guanidine and a carboxyl
terminal groups spaced by a chain of 11 atoms, at least 5 of said
atoms being carbon atoms, and said chain comprises one or more O, S
or N atoms and may optionally be substituted by oxo, thioxo,
halogen, amino, C1-C6 alkyl, hydroxyl, or carboxy or one or more
atoms of said chain may form a 3-6 membered carbocyclic or
heterocyclic ring. Compounds of this type are described in WO
93/09795 of the same applicant, herein incorporated by reference in
its entirety as if fully disclosed herein.
In preferred embodiments, the RGD peptidomimetic above comprises in
the chain N atoms and is substituted by an oxo group.
In a more preferred embodiment, the RGD peptidomimetic has the
formula shown in conjugate 40 herein:
H.sub.2N--C(.dbd.NH)NH--(CH.sub.2).sub.5--CO--NH--CH(CH.sub.2)--(CH.sub.2-
).sub.2--COOH In another embodiment, the RGD peptidomimetic has the
formula shown in conjugate 41 herein.
In one embodiment, the photosensitizer is a porphyrin that may be
metalated or unmetalated and optionally substituted in the
periphery by different substituents such as alkyl, aryl, heteroaryl
and or functional groups. Most preferred porphyrins used in
accordance with the present invention are water-soluble
porphyrins.
In preferred embodiments, the porphyrin macrocycle is substituted
by 4 aryl groups at positions 5, 10, 15, 20.
In one preferred embodiment, the photosensitizer is a
tetraarylporphyrin of the formula:
##STR00001## wherein
Ar.sub.1, Ar.sub.2, Ar.sub.3, and Ar.sub.4, the same or different,
are each an aryl radical selected from a carbocyclic aryl, a
heteroaryl and a mixed carboaryl-heteroaryl radical, each of the
aryl radicals is unsubstituted or is substituted by one or more
substituents selected from halogen atoms, C.sub.2-C.sub.8 alkyl
when the aryl is phenyl, C.sub.1-C.sub.8 alkyl when the aryl is
heteroaryl or mixed carboaryl-heteroaryl, C.sub.1-C.sub.8alkoxy,
carboxy, C.sub.1-C.sub.8 alkylamino, amino-(C.sub.1-C.sub.8)
alkylamino, tri-(C.sub.1-C.sub.8) alkylammonium, hydroxy, and
CONH.sub.2, and at least one of Ar.sub.1, Ar.sub.2, Ar.sub.3, and
Ar.sub.4 is substituted by an RGD-containing peptide or an RGD
peptidomimetic linked to said at least one aryl group via one of
its substituents or via a bridging group;
n is 0 when the substituents are neutral, or n is an integer from 1
to 4;
X is a pharmaceutically acceptable anion, when the aryl groups are
positively charged, or a pharmaceutically acceptable cation, when
the aryl groups are negatively charged; and
M is 2H or is an atom selected from the group consisting of Mg, Pd,
Pt, Co, Ni, Sn, Cu, Zn, Mn, In, Eu, Fe, Au, Al, Gd, Er, Yb, Lu, Ga,
Y, Rh, Ru, Si, Ge, Cr, Mo, P, Re, Tl and Tc and isotopes
thereof.
In preferred embodiments, the RGD-porphyrin conjugates are utilized
in diagnosis and/or radiotherapy. According to these embodiments,
the porphyrins are metalated porphyrins wherein the metal atom is
preferably Mn, Cu, or Ni. When the conjugates of the invention are
utilized for diagnosis, for example, of tumors, the porphyrins are
metalated with radioisotopes such as .sup.103Pd, .sup.195Pt,
.sup.105Rh, .sup.106Rh, .sup.188Re, .sup.177Lu, .sup.164Er,
.sup.117mSn, .sup.153Sm, .sup.90Y, .sup.67Cu and .sup.32P.
In certain other embodiments, the RGD-porphyrin conjugates are
utilized in photodynamic therapy (PDT). The preferred porphyrins
according to these embodiments are non-metalated porphyrins or
porphyrin containing certain metal atoms selected from Co, Pd, Pt
or Ru. Cytotoxicity of metalated porphyrins may be enhanced by
introduction of positively or negatively charged groups
thereto.
Photophysical properties (visible absorption, fluorescence and
triplet lifetime) of the metalated metalloporphyrin derivatives are
determined by the central metal. Ando et al. (Ando et al., 1993)
showed that a Zn-porphyrin derivative had longer triplet lifetimes
(>1 ms) and the triplet lifetime of the Ga porphyrin was even
longer (40.3 ms). On the other hand, Cu-porphyrin had a much
shorter triplet lifetime than other metalated porphyrins. In fact,
the triplet lifetimes of Mn-, Fe- and Ni-porphyrins were
unmeasurable because they did not emit any detectable fluorescence
or phosphorescence. This means that they have triplet lifetimes
shorter than 0.1 The absence of fluorescence and phosphorescence of
these derivatives can be connected with increase of the
radiationless decay from the lowest singlet state as well as from
the lowest excited triplet state to result in significant reduction
of the triplet lifetime.
Thus, apparently, porphyrins containing metal atom such as Mn, Cu,
Gd, Zn, Fe(II) or Ni do not react well with tissue oxygen and,
therefore, do not generate the critical amount of reactive oxygen
species (ROS) needed to elicit an efficient PDT effect. Indeed, it
was shown (Ali and van Lier, 1999; Tomoyuki et al., 1993) that
.sup.67Cu- and Ni-porphyrins are non-toxic and exhibit good in vivo
stability, and Mn(III)-porphyrins are usually not active as
photosensitizers and thus avoid side effects such as skin
photosensitivity.
Based on such observations, the present inventors designed
tetrarylporphyrin derivatives metalated with Mn, Ni, Cu, Gd, Zn or
Fe(II) as diagnostic agents, suitable for concomitant use in
diagnostic techniques such as, but not limited to, magnetic
resonance imaging.
The carbocyclic aryl radical by itself or as part of the mixed
carboaryl-heteroaryl radical may be a substituted or unsubstituted
monocyclic or bicyclic aromatic radical and said heteroaryl radical
by itself or as part of a mixed carboaryl-heteroaryl radical may be
a substituted or unsubstituted 5-6 membered aromatic ring
containing 1-3 heteroatoms selected from O, S and/or N.
Examples of carbocyclic aryl radical include phenyl, biphenyl and
naphthyl and of heteroaryl include furyl, thienyl, pyrrolyl,
imidazolyl, thiazolyl, pyridyl, pyrimidyl, and triazinyl. The
carbocyclic aryl and/or heteroaryl radical may be unsubstituted or
substituted by one or more halogen atoms, C.sub.1-C.sub.8 alkyl,
C.sub.1-C.sub.8alkoxy, carboxy, C.sub.1-C.sub.8 alkylamino,
amino-(C.sub.1-C.sub.8) alkylamino, and tri-(C.sub.1-C.sub.8)
alkylammonium radicals, carboxy, CONH.sub.2, with the proviso that
M is not 2H when the carbocyclic aryl is phenyl substituted by
methyl or tetraacetylglucosyloxy and the RGD peptide is linear.
In the tetraaryl porphirins above M is preferably 2H, Pd, Cu, Mn or
Gd.
In one preferred embodiment, the RGD peptide in the conjugate
containing a porphyrin photosensitizer is the peptide of SEQ ID
NO:1, preferably linked to at least one aryl group of the porphyrin
moiety via a --CO--NH-- group.
In preferred embodiments, the RGD peptide-porphyrin conjugates
comprise a non-metalated or metalated tetraarylporphyrin conjugated
to the peptide of SEQ ID
NO:1:Meso-5-(4-cycloRGDfK-benzamido)-10,15,20-tris(4-carboxyphe-
nyl) porphine (20); Copper(II)
meso-5-(4-cycloRGDfK-benzamido)-10,15,20-tris(4-carboxyphenyl)
porphine (21); and Gadolinium(III)
meso-5-(4-cycloRGDfK-benzamido)-10,15,20-tris(4-carboxyphenyl)porphine
(22).
In another embodiment, the photosensitizer is a chlorophyll or
bacteriochlorophyll derivative that may be a natural or a synthetic
non-natural derivative of chlorophyll or bacteriochlorophyll,
including compounds in which modifications have been made in the
macrocycle, and/or in the periphery and/or the central Mg atom may
be absent or it is replaced by other metal atom suitable for the
purpose of diagnosis and/or for the purpose of PDT.
In preferred embodiments, the invention relates to a conjugate
wherein the photosensitizer is a chlorophyll or bacteriochlorophyll
of the formula I, II or III:
##STR00002## wherein
M represents 2H or an atom selected from the group consisting of
Mg, Pd, Pt, Co, Ni, Sn, Cu, Zn, Mn, In, Eu, Fe, Au, Al, Gd, Er, Yb,
Lu, Ga, Y, Rh, Ru, Si, Ge, Cr, Mo, P, Re and Tc and isotopes
thereof;
X is O or N--R.sub.7;
R.sub.1, R'.sub.2 and R.sub.6 each independently is Y--R.sub.8,
--NR.sub.9R'.sub.9 or --N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-
or R.sub.1 and R.sub.6 in formula II together with the carbon atoms
to which they are attached form a ring comprising an RGD peptide or
RGD peptidomimetic;
Y is O or S;
R.sub.2 is H, OH or COORS;
R.sub.3 is H, OH, C.sub.1-C.sub.12 alkyl or C.sub.1-C.sub.12
alkoxy;
R.sub.4 is --CH.dbd.CR.sub.9R'.sub.9, --CH.dbd.CR.sub.9Hal,
--CH.dbd.CH--CH.sub.2--NR.sub.9R'.sub.9,
--CH.dbd.CH--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--CHO, --CH.dbd.NR.sub.9, --CH.dbd.N.sup.+R.sub.9R'.sub.9A.sup.-,
--CH.sub.2--OR.sub.9, --CH.sub.2--SR.sub.9, --CH.sub.2-Hal,
--CH.sub.2--R.sub.9, --CH.sub.2--NR.sub.9R.sub.9,
--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--CH.sub.2--CH.sub.2R.sub.9, --CH.sub.2--CH.sub.2Hal,
--CH.sub.2--CH.sub.2OR.sub.9, --CH.sub.2--CH.sub.2SR.sub.9,
--CH.sub.2--CH.sub.2--NR.sub.9R'.sub.9,
--CH.sub.2--CH.sub.2--N.sup.+R.sub.9R'.sub.9R''.sub.9A.sup.-,
--COCH.sub.3, C(CH.sub.3).dbd.CR.sub.9R'.sub.9,
--C(CH.sub.3).dbd.CR.sub.9Hal, --C(CH.sub.3).dbd.NR.sub.9,
--CH(CH.sub.3).dbd.N.sup.+R.sub.9R'.sub.9A.sup.-,
--CH(CH.sub.3)-Hal, --CH(CH.sub.3)--OR.sub.9,
--CH(CH.sub.3)--SR.sub.9, --CH(CH.sub.3)--NR.sub.9R'.sub.9,
--CH(CH.sub.3)--N.sup.+R.sub.9R'.sub.9R'.sub.9A.sup.-, or
--C.ident.CR.sub.9;
R'.sub.4 is methyl or formyl;
R.sub.5 is .dbd.O, .dbd.S, .dbd.N--R.sub.9,
.dbd.N.sup.+R.sub.9R'.sub.9A.sup.-, .dbd.CR.sub.9R'.sub.9, or
.dbd.CR.sub.9-Hal; R.sub.7, R.sub.8, R.sub.9, R'.sub.9 and
R''.sub.9 each independently is:
(a) H;
(b) C.sub.1-C.sub.25 hydrocarbyl;
(c) C.sub.1-C.sub.25 hydrocarbyl, preferably C.sub.1-C.sub.25
alkyl, alkenyl or alkynyl, more preferably C.sub.1-C.sub.10 or
C.sub.1-C.sub.6 alkyl, substituted by one or more functional groups
selected from the group consisting of halogen, nitro, oxo, OR, SR,
epoxy, epithio, --NRR', --CONRR', --CONR--NRR', --NHCONRR',
--NHCONRNRR', --COR, COOR'', --OSO.sub.3R, --SO.sub.3R'',
--SO.sub.2R, --NHSO.sub.2R, --SO.sub.2NRR', .dbd.N--OR,
--(CH.sub.2).sub.n--CO--NRR', --O--(CH.sub.2).sub.n--OR,
--O--(CH.sub.2).sub.n--O--(CH.sub.2).sub.n--R, --OPO.sub.3RR',
--PO.sub.2HR, and --PO.sub.3R''R'', wherein R and R' each
independently is H, hydrocarbyl or heterocyclyl and R'' is
hydrocarbyl or heterocyclyl;
(d) C.sub.1-C.sub.25 hydrocarbyl, preferably C.sub.1-C.sub.25
alkyl, more preferably C.sub.1-C.sub.10 or C.sub.1-C.sub.6 alkyl,
substituted by one or more functional groups selected from the
group consisting of positively charged groups, negatively charged
groups, basic groups that are converted to positively charged
groups under physiological conditions, and acidic groups that are
converted to negatively charged groups under physiological
conditions;
(e) C.sub.1-C.sub.25 hydrocarbyl, preferably C.sub.1-C.sub.25
alkyl, more preferably C.sub.1-C.sub.10 or C.sub.1-C.sub.6 alkyl,
containing one or more heteroatoms and/or one or more carbocyclic
or heterocyclic moieties;
(f) C.sub.1-C.sub.25 hydrocarbyl, preferably C.sub.1-C.sub.25
alkyl, more preferably C.sub.1-C.sub.10 or C.sub.1-C.sub.6 alkyl,
containing one or more heteroatoms and/or one or more carbocyclic
or heterocyclic moieties and substituted by one or more functional
groups as defined in (c) and (d) above;
(g) C.sub.1-C.sub.25 hydrocarbyl, preferably C.sub.1-C.sub.25
alkyl, more preferably C.sub.1-C.sub.10, or C.sub.1-C.sub.6 alkyl
substituted by a residue of an amino acid, a peptide, a protein, a
monosaccharide, an oligosaccharide, a polysaccharide, or a
polydentate ligand and its chelating complex with metals; or
(h) a residue of an amino acid, a peptide, a protein, a
monosaccharide, an oligosaccharide, a polysaccharide, or a
polydentate ligand and its chelating complex with metals;
R.sub.7 may further be --NRR', wherein R and R' each is H or
C.sub.1-C.sub.25 hydrocarbyl, preferably C.sub.1-C.sub.2 alkyl,
more preferably C.sub.1-C.sub.10 or C.sub.1-C.sub.6 alkyl,
optionally substituted by a negatively charged group, preferably
SO.sub.3.sup.-;
R.sub.8 may further be H.sup.+ or a cation R.sup.+.sub.10 when
R.sub.1, R'.sub.2 and R.sub.6 each independently is Y--R.sub.8;
R.sup.+.sub.10 is a metal, an ammonium group or an organic
cation;
A.sup.- is a physiologically acceptable anion;
m is 0 or 1;
the dotted line at positions 7-8 represents an optional double
bond; and
pharmaceutically acceptable salts and optical isomers thereof;
and said chlorophyll or bacteriochlorophyll derivative of formula
I, II or III contains at least one RGD-containing peptide
residue.
In one embodiment, the dotted line at positions 7-8 represents a
double bond and the photosensitizer is a chlorophyll of the formula
I, II or III. The compounds of formula I wherein M is Mg, R.sub.1
at position 17.sup.3 is phytyloxy, R.sub.2 at position 13.sup.2 is
COOCH.sub.3, R.sub.3 at position 13.sup.2 is an H atom, R.sub.5 is
O, R.sub.4 at position 3 is vinyl, the dotted line at positions 7-8
represents a double bond, and either R'.sub.4 is methyl at position
7 and R.sub.4 is ethyl at position 8 or R'.sub.4 is formyl at
position 7 and R.sub.4 is ethyl at position 8, are chlorophyll a
and b, respectively, and their derivatives will have different
metal atom and/or different substituents R.sub.1, R.sub.2, R.sub.3,
R.sub.4, R'.sub.4 and/or R.sub.5.
In another embodiment, the positions 7-8 are hydrogenated and the
photosensitizer is a bacteriochlorophyll of the formula I, II or
III. The compounds of formula I wherein M is Mg, R.sub.1 at
position 17.sup.3 is phytyloxy or geranylgeranyloxy, R.sub.2 at
position 13.sup.2 is COOCH.sub.3, R.sub.3 at position 13.sup.2 is
an H atom, R.sub.5 is O, R.sub.4 at position 3 is acetyl and at
position 8 is ethyl, and the dotted line at positions 7-8 is absent
are bacteriochlorophyll a, and their derivatives will have
different metal atom and/or different substituents R.sub.1,
R.sub.2, R.sub.3, R.sub.4, and/or R.sub.5.
As used herein, the term "hydrocarbyl" means any straight or
branched, saturated or unsaturated, acyclic or cyclic, including
aromatic, hydrocarbyl radicals, of 1-25 carbon atoms, preferably of
1 to 20, more preferably 1 to 6, most preferably 2-3 carbon atoms.
The hydrocarbyl may be an alkyl radical, preferably of 1-4 carbon
atoms, e.g. methyl, ethyl, propyl, butyl, or alkenyl, alkynyl,
cycloalkyl, aryl such as phenyl or an aralkyl group such as benzyl,
or at the position 17 it is a radical derived from natural Chl and
Bchl compounds, e.g. geranylgeranyl (2,6-dimethyl-2,6-octadienyl)
or phytyl (2,6,10,14-tetramethyl-hexadec-14-en-16-yl).
As used herein, the term "carbocyclic moiety" refers to a
monocyclic or polycyclic compound containing only carbon atoms in
the ring(s). The carbocyclic moiety may be saturated, i.e.
cycloalkyl, or unsaturated, i.e. cycloalkenyl, or aromatic, i.e.
aryl.
The term "alkoxy" as used herein refers to a group
(C.sub.1-C.sub.25)alkyl-O--, wherein C.sub.1-C.sub.25 alkyl is as
defined above. Examples of alkoxy are methoxy, ethoxy, n-propoxy,
isopropoxy, butoxy, isobutoxy, tert-butoxy, pentoxy, hexoxy,
--OC.sub.15H.sub.31, --OC.sub.16H.sub.33, --OC.sub.17H.sub.35,
--OC.sub.18H.sub.37, and the like. The term "aryloxy" as used
herein refers to a group (C.sub.6-C.sub.18)aryl-O--, wherein
C.sub.6-C.sub.18 aryl is as defined above, for example, phenoxy and
naphthoxy.
The terms "heteroaryl" or "heterocyclic moiety" or "heteroaromatic"
or "heterocyclyl", as used herein, mean a radical derived from a
mono- or poly-cyclic heteroaromatic ring containing one to three
heteroatoms selected from the group consisting of O, S and N.
Particular examples are pyrrolyl, furyl, thienyl, pyrazolyl,
imidazolyl, oxazolyl, thiazolyl, pyridyl, quinolinyl, pyrimidinyl,
1,3,4-triazinyl, 1,2,3-triazinyl, 1,3,5-triazinyl, benzofuryl,
isobenzofuryl, indolyl, imidazo[1,2-a]pyridyl, benzimidazolyl,
benzthiazolyl and benzoxazolyl.
Any "carbocyclic", "aryl" or "heteroaryl" may be substituted by one
or more radicals such as halogen, C.sub.6-C.sub.14 aryl,
C.sub.1-C.sub.25 alkyl, nitro, OR, SR, --COR, --COOR, --SO.sub.3R,
--SO.sub.2R, --NHSO.sub.2R, --NRR', --(CH.sub.2).sub.n--NR--COR',
and --(CH.sub.2).sub.n--CO--NRR'. It is to be understood that when
a polycyclic heteroaromatic ring is substituted, the substitutions
may be in any of the carbocyclic and/or heterocyclic rings.
The term "halogen", as used herein, refers to fluoro, chloro, bromo
or iodo.
In one embodiment of the invention, the photosensitizer of the
conjugate is a chlorophyll or bacteriochlorophyll of the formula I,
II or III containing at least one negatively charged group and/or
at least one acidic group that is converted to a negatively charged
group at the physiological pH.
As defined herein, "a negatively charged group" is an anion derived
from an acid and includes carboxylate (COO.sup.-), thiocarboxylate
(COS.sup.-), sulfonate (SO.sub.3.sup.-), and phosphonate
(PO.sub.3.sup.2-), and the "acidic group that is converted to a
negatively charged group under physiological conditions" include
the carboxylic (--COOH), thio-carboxylic (--COSH), sulfonic
(--SO.sub.3H) and phosphonic (--PO.sub.3H.sub.2) acid groups. BChl
derivatives with negatively charged groups or groups converted
thereto under physiological conditions have been described in WO
2004/045492 of the same applicant, herewith incorporated by
reference in its entirety as if fully disclosed herein.
In another embodiment of the invention, the photosensitizer of the
conjugate is a chlorophyll or bacteriochlorophyll of the formula I,
II or III containing at least one positively charged group and/or
at least one basic group that is converted to a positively charged
group at the physiological pH.
As defined herein, "a positively charged group" denotes a cation
derived from a N-containing group or from an onium group not
containing N. Since tumor endothelium is characterized by an
increased number of anionic sites, positively charged groups or
basic groups that are converted to positively charged groups under
physiological conditions, may enhance the targeting efficiency of
the conjugates of the present invention.
A "cation derived from a N-containing group" as used herein
denotes, for example, but is not limited to, an ammonium
--N.sup.+(RR'R''), hydrazinium --(R)N--N.sup.+(R'R''), ammoniumoxy
O.rarw.N.sup.+(RR')--, iminium >C.dbd.N.sup.+(RR'), amidinium
--C(.dbd.RN)--N.sup.+R'R'' or guanidinium
--(R)N--C(.dbd.NR)--N.sup.+R'R'' group, wherein R, R' and R'' each
independently is H, hydrocarbyl, preferably C.sub.1-C.sub.6 alkyl
as defined herein, phenyl or benzyl, or heterocyclyl, or in the
ammonium group one of R, R' and R'' may be OH, or two of R, R' and
R'' in the ammonium group or R and R' in the hydrazinium,
ammoniumoxy, iminium, amidinium or guanidinium groups, together
with the N atom to which they are attached, form a 3-7 membered
saturated ring, optionally containing one or more heteroatoms
selected from the group consisting of O, S or N and optionally
further substituted at the additional N atom, or said cation is
derived from a compound containing one or more N atoms in a
heteroaromatic ring.
In one more preferred embodiment, the conjugate of the present
invention contains an ammonium group of the formula
--N.sup.+(RR'R''), wherein each of R, R' and R'' independently is H
or optionally substituted hydrocarbyl or heterocyclyl, as defined
herein, or one of them may be OH. The --N.sup.+(RR'R'') ammonium
group may be a secondary ammonium, wherein any two of the radicals
R, R' or R'' are H; a tertiary ammonium, wherein only one of R, R'
or R'' is H; or a quaternary ammonium, wherein each of R, R' or R''
is an optionally substituted hydrocarbyl or heterocyclyl group as
defined herein. When one of R, R' or R'' is OH, the group is a
hydroxylammonium group. Preferably, the ammonium group is a
quaternary ammonium group wherein R, R' and R'' each is
C.sub.1-C.sub.6 alkyl such as methyl, ethyl, propyl, butyl, hexyl.
As mentioned hereinabove, the ammonium group may be an end group in
the molecule or it may be found within an alkyl chain in the
molecule.
In the hydrazinium --(R)N--N.sup.+(R'R''), amidinium
--C(.dbd.NR)--N.sup.+R'R'' and guanidinium
--(R)N--C(.dbd.NR)--N.sup.+R'R'' groups, R, R' and R'' may each
independently be H or hydrocarbyl or heterocyclyl, or R' and R''
together with the N atom to which they are attached form a 3-7
membered saturated ring, as defined herein. Examples of such groups
include those wherein R is H, and R' and R'' each is
C.sub.1-C.sub.6 alkyl such as methyl, ethyl, propyl, butyl,
hexyl.
In the ammoniumoxy O.rarw.N.sup.+(RR')-- and iminium
>C.dbd.N.sup.+(RR') groups, R and R' may each independently be H
or hydrocarbyl, preferably C.sub.1-C.sub.6 alkyl, or heterocyclyl,
or R and R' together with the N atom to which they are attached
form a 3-7 membered saturated ring, as defined herein.
In another preferred embodiment, the bacteriochlorophyll derivative
contains a cyclic ammonium group of the formula --N.sup.+(RR'R''),
wherein two of R, R' and R'' together with the N atom form a 3-7
membered saturated ring defined hereinbelow.
As defined herein, "a 3-7 membered saturated ring" formed by two of
R, R' and R'' together with the N atom to which they are attached
may be a ring containing only N such as aziridine, pyrrolidine,
piperidine, piperazine or azepine, or it may contain a further
heteroatom selected from O and S such as morpholine or
thiomorpholine. The further N atom in the piperazine ring may be
optionally substituted by alkyl, e.g. C.sub.1-C.sub.6 alkyl, that
may be substituted by halo, OH or amino. The onium groups derived
from said saturated rings include aziridinium, pyrrolidinium,
piperidinium, piperazinium, morpholinium, thiomorpholinium and
azepinium.
As defined herein "a cation derived from a N-containing
heteroaromatic radical" denotes a cation derived from a
N-heteroaromatic compound that may be a mono- or polycyclic
compound optionally containing O, S or additional N atoms. The ring
from which the cation is derived should contain at least one N atom
and be aromatic, but the other ring(s), if any, can be partially
saturated. Examples of N-heteroaromatic cations include pyrazolium,
imidazolium, oxazolium, thiazolium, pyridinium, pyrimidinium,
quinolinium, isoquinolinium, 1,2,4-triazinium, 1,3,5-triazinium and
purinium.
The at least one positively charged group may also be an onium
group not containing nitrogen such as but not limited to,
phosphonium [--P.sup.+(RR'R'')], arsonium [--As.sup.+(RR'R'')],
oxonium [--O.sup.+(RR')], sulfonium [--S.sup.+(RR')], selenonium
[--Se.sup.+(RR')], telluronium [--Te.sup.+(RR')], stibonium
[--Sb.sup.+(RR'R'')], or bismuthonium [--Bi.sup.+(RR'R'')] group,
wherein each of R, R' and R'', independently, is H, hydrocarbyl or
heterocyclyl, preferably C.sub.1-C.sub.6 alkyl such as methyl,
ethyl, propyl, butyl, pentyl or hexyl, or aryl, preferably,
phenyl.
Examples of phosphonium groups of the formula --P.sup.+(RR'R'')
include groups wherein R, R' and R'' each is methyl, ethyl, propyl,
butyl or phenyl, or R is methyl, ethyl, propyl, butyl or hexyl and
R' and R'' both are phenyl. Examples of arsonium groups of the
formula --As.sup.+(RR'R'') include groups wherein R, R' and R''
each is methyl, ethyl, propyl, butyl or phenyl. Examples of
sulfonium groups of the formula --S.sup.+(RR') include groups
wherein R and R' each is methyl, ethyl, propyl, butyl, phenyl,
benzyl, phenethyl, or a substituted hydrocarbyl group.
As defined herein, "a basic group that is converted to a positively
charged group under physiological conditions" is, at least
theoretically, any basic group that will generate under
physiological conditions a positively charged group as defined
herein. It is to be noted that the physiological conditions, as
used herein, do not refer solely to the serum, but to different
tissues and cell compartments in the body.
Examples of such N-containing basic groups include, without being
limited to, any amino group that will generate an ammonium group,
any imine group that will generate an iminium group, any hydrazine
group that will generate a hydrazinium group, any aminooxy group
that will generate an ammoniumoxy group, any amidine group that
will generate an amidinium group, any guanidine group that will
generate a guanidinium group, all as defined herein. Other examples
include phosphino and mercapto groups.
Thus, the conjugates of the present invention may contain at least
one basic group that is converted to a positively charged group
under physiological conditions such as --NRR',
--C(.dbd.NR)--NR'R'', --NR--NR'R'', --(R)N--C(.dbd.NR)--NR'R'',
O--NR--, or >C.dbd.NR, wherein each of R, R' and R''
independently is H, hydrocarbyl, preferably C.sub.1-C.sub.25 alkyl,
more preferably C.sub.1-C.sub.10 or C.sub.1-C.sub.6 alkyl, or
heterocyclyl, or two of R, R' and R'' together with the N atom form
a 3-7 membered saturated ring, optionally containing an O, S or N
atom and optionally further substituted at the additional N atom,
or the basic group is a N-containing heteroaromatic radical.
The 3-7 membered saturated ring may be aziridine, pyrrolidine,
piperidine, morpholine, thiomorpholine, azepine or piperazine
optionally substituted at the additional N atom by C.sub.1-C.sub.6
alkyl optionally substituted by halo, hydroxyl or amino, and the
N-containing heteroaromatic radical may be pyrazolyl, imidazolyl,
oxazolyl, thiazolyl, pyridyl, quinolinyl, isoquinolinyl, pyrimidyl,
1,2,4-triazinyl, 1,3,5-triazinyl or purinyl.
BChl derivatives with positively charged groups or groups converted
thereto under physiological conditions have been described in WO
2005/120573 of the same applicant, herewith incorporated by
reference in its entirety as if fully disclosed herein.
In one embodiment, the photosensitizer is a chlorophyll or
bacteriochlorophyll of formula II and R.sub.6 is a basic group
--NR.sub.9R'.sub.9 wherein R.sub.9 is H and R'.sub.9 is
C.sub.1-C.sub.6 alkyl substituted by a basic group
--NH--(CH.sub.2).sub.2-6--NRR' wherein each of R and R'
independently is H, C.sub.1-C.sub.6 alkyl optionally substituted by
NH.sub.2 or R and R' together with the N atom form a 5-6 membered
saturated ring, optionally containing an O or N atom and optionally
further substituted at the additional N atom by
--(CH.sub.2).sub.2-6--NH.sub.2.
In another embodiment, the photosensitizer is a bacteriochlorophyll
of formula II and R.sub.6 is
--NH--(CH.sub.2).sub.3--NH--(CH.sub.2).sub.3--NH.sub.2,
--NH--(CH.sub.2).sub.2-1-morpholino, or
--NH--(CH.sub.2).sub.3-piperazino-(CH.sub.2).sub.3--NH.sub.2 or
R.sub.1 and R.sub.6 together form a cyclic ring comprising an RGD
peptide or RGD peptidomimetic.
In another embodiment, the photosensitizer is a chlorophyll or
bacteriochlorophyll of formula III, X is --NR.sub.7, R.sub.7 is
--NRR', R is H and R' is C.sub.2-6-alkyl substituted by SO.sub.3--
or an alkaline salt thereof, preferably the photosensitizer is a
bacteriochlorophyll and X is --NR.sub.7 and R.sub.7 is
--NH--(CH.sub.2).sub.3--SO.sub.3K.
In another embodiment, R.sub.7, R.sub.8, R.sub.9 or R'.sub.9 each
is a C.sub.1-6-alkyl substituted by one or more --OH groups. For
example, the photosensitizer is a chlorophyll or
bacteriochlorophyll of formula II and R.sub.6 is
--NR.sub.9R'.sub.9, R.sub.9 is H and R'.sub.9 is
HOCH.sub.2--CH(OH)--CH.sub.2--.
In another embodiment, the photosensitizer is a chlorophyll or
bacterio-chlorophyll of formula II and R.sub.6 is
--NR.sub.9R'.sub.9, R.sub.9 is H and R'.sub.9 is C.sub.1-6-alkyl
substituted by a polydentate ligand or its chelating complexes with
metals. Examples of polydentate ligands include, without being
limited to, EDTA (etlylenediamine tetraacetic acid), DTPA
(diethylene triamine pentaacetic acid) or the macrocyclic ligand
DOTA. In one preferred embodiment the polydentate ligand is DTPA,
R.sub.6 is --NH--(CH.sub.2).sub.3--NH-DTPA, and the metal is
Gd.
The cation R.sub.8.sup.+ may be a monovalent or divalent cation
derived from an alkaline or alkaline earth metal such as K.sup.+,
Na.sup.+, Li.sup.+, NH.sub.4.sup.+, Ca.sup.2+, more preferably
K.sup.+; or R.sub.8.sup.+ is an organic cation derived from an
amine or from a N-containing group
As defined herein, the C.sub.1-C.sub.25 hydrocarbyl defined for
R.sub.7, R.sub.8, R.sub.9 and R'.sub.9 may optionally be
substituted by one or more functional groups selected from halogen,
nitro, oxo, OR, SR, epoxy, epithio, aziridine, --CONRR', --COR,
COOR, --OSO.sub.3R, --SO.sub.3R, --SO.sub.2R, --NHSO.sub.2R,
--SO.sub.2NRR'--NRR', .dbd.N--OR, .dbd.N--NRR', --C(.dbd.NR)--NRR',
--NR--NRR', --(R)N--C(.dbd.NR)--NRR', O.rarw.NR--, >C.dbd.NR,
--(CH.sub.2).sub.n--NR--COR', --(CH.sub.2).sub.n--CO--NRR',
--O--(CH.sub.2).sub.n--OR,
--O--(CH.sub.2).sub.n--O--(CH.sub.2).sub.n--R, --PRR',
--OPO.sub.3RR', --PO.sub.2HR, --PO.sub.3RR'; one or more negatively
charged groups such as COO.sup.-, COS.sup.-, --OSO.sub.3.sup.-,
--SO.sub.3.sup.-, --OPO.sub.3R.sup.-, --PO.sub.2H.sup.-,
--PO.sub.3.sup.2- and --PO.sub.3R.sup.-; and/or one or more
positively charged groups such as --P+(RR'R''), --As.sup.+(RR'R''),
--O.sup.+(RR'), --S+(RR'), --Se.sup.+(RR'), --Te.sup.+(RR'),
--Sb.sup.+(RR'R''), --Bi.sup.+(RR'R''), O--N.sup.+(RR')--,
>C.dbd.N.sup.+(RR'), --N.sup.+(RR'R''), --(R)N--N.sup.+(RR'R''),
--(R)N--C(.dbd.HN)--N.sup.+RR'R'', --C(.dbd.NH)--N.sup.+(RR'R''),
or a N-heteroaromatic cation such as pyrazolium, imidazolium,
oxazolium, thiazolium, pyridinium, quinolinium, pyrimidinium,
1,2,4-triazinium, 1,3,5-triazinium and purinium; wherein n is an
integer from 1 to 6, R, R' and R'' each independently is H,
hydrocarbyl or heterocyclyl, or two of R, R' and R'' together with
the N atom to which they are attached form a 3-7 membered saturated
ring, optionally containing one or more heteroatoms selected from
the group consisting of O, S or N and optionally further
substituted at the additional N atom. The C.sub.1-C.sub.25
hydrocarbyl defined for R.sub.7, R.sub.8, R.sub.9 and R'.sub.9 may
also be substituted by the residue of a mono-, oligo- or
polysaccharide such as glycosyl, or of an amino acid, peptide or
protein. In addition, R.sub.8, R.sub.9 and R'.sub.9 each may
independently be a residue of a mono-, oligo- or polysaccharide
such as glycosyl, or of an amino acid, peptide or protein, or a
polydentate ligand such as DTPA, DOTA, EDTA and the like and their
chelating complexes with metals.
In the groups OR and SR, when R is H, the groups hydroxy and
mercapto are represented, respectively, and when R is other than H,
ethers and sulfides are represented. In the group --PRR', the
phosphino group is represented when R and R' are H. In the group
--COR, when R is H, the formyl group --CHO of an aldehyde is
represented, while when R is other than H, this is the residue of a
ketone such as alkylcarbonyl and arylcarbonyl groups. In the group
COOR, when R is not H, this is a carboxylic acid ester group such
as the alkoxycarbonyl and aryloxycarbonyl groups. Similarly, esters
are represented in the groups --OSO.sub.3R, --SO.sub.3R,
--SO.sub.2R, --OPO.sub.3RR', --PO.sub.2HR and --PO.sub.3RR' when R
and R' are other than H.
In one preferred embodiment of the invention, the photosensitizer
is unmetalated, namely, M is 2H. In other preferred embodiments,
the photosensitizer is metalated as defined hereinabove, more
preferably M is Pd, Cu or Mn, most preferably Pd.
In some preferred embodiments of the invention, the photosensitizer
is a bacteriochlorophyll of the formula I, II or III, more
preferably formula II, and M is 2H, Cu, Mn, more preferably Pd. In
other embodiments, the photosensitizer is a chlorophyll of the
formula I, II or III, more preferably formula II, and M is 2H, Cu
or Mn.
In some preferred embodiments, the conjugate comprises a
photosensitizer bacteriochlorophyll of the formula II wherein M is
Pd, Mn, Cu or 2H; m is 0; R.sub.1 is NH--P, wherein P is the
residue of an RGD-containing peptide or RGD peptidomimetic linked
directly to the NH-- or via a spacer; R'.sub.2 is methoxy; R.sub.4
at position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; and R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3.sup.-Me.sup.+, wherein Me.sup.+ is
Na.sup.+ or K.sup.+.
In other preferred embodiments, the conjugate comprises a
photosensitizer bacteriochlorophyll of the formula II wherein M is
Pd or 2H; m is 0; R.sub.1 is NH--P, wherein P is the residue of an
RGD-containing peptide or RGD peptidomimetic linked directly to the
NH-- or via a spacer; R'.sub.2 is methoxy; R.sub.4 at position 3 is
acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6
is --NH--CH.sub.2--CH(OH)--CH.sub.2--OH.
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula III wherein M is Pd; R.sub.1 is
NH--P, wherein P is the residue of an RGD-containing peptide or RGD
peptidomimetic linked directly to the NH-- or via a spacer; R.sub.4
at position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; X is N--R.sub.7 and R.sub.7 is
--NH--(CH.sub.2).sub.3--SO.sub.3.sup.-Me.sup.+, wherein Me.sup.+ is
Na.sup.+ or K.sup.+.
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula I wherein M is Mn; R.sub.1 is
NH--P, wherein P is the residue of an RGD-containing peptide or RGD
peptidomimetic linked directly to the NH-- or via a spacer; R.sub.2
is OH; R.sub.3 is COOCH.sub.3; R.sub.4 at position 3 is acetyl and
at position 8 is ethyl; R'.sub.4 is methyl; and R5 is O.
In another embodiment, the conjugate comprises a chlorophyll of the
formula II wherein M is selected from Mn, Cu or 2H; R.sub.1 is
NH--P, wherein P is the residue of an RGD-containing peptide or RGD
peptidomimetic linked directly to the NH-- or via a spacer; R.sub.4
at position 3 is vinyl and at position 8 is ethyl; R'.sub.4 is
methyl; and R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3.sup.-Me.sup.+, wherein Me.sup.+ is
Na.sup.+ or K.sup.+.
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is 2H; m is 0;
R.sub.1 is NH--P, wherein P is the residue of an RGD-containing
peptide or RGD peptidomimetic linked directly to the NH-- or via a
spacer; R'.sub.2 is methoxy; R.sub.4 at position 3 is acetyl and at
position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6 is
--NH--(CH.sub.2).sub.3--NH--(CH.sub.2).sub.3--NH.sub.2.
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is 2H; m is 0;
R.sub.1 is NH--P, wherein P is the residue of an RGD-containing
peptide or RGD peptidomimetic linked directly to the NH-- or via a
spacer; R'.sub.2 is methoxy; R.sub.4 at position 3 is acetyl and at
position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6 is
--NH--(CH.sub.2).sub.2-morpholino.
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is 2H; m is 0;
R.sub.1 is NH--P, wherein P is the residue of an RGD-containing
peptide or RGD peptidomimetic linked directly to the NH-- or via a
spacer; R'.sub.2 is methoxy; R.sub.4 at position 3 is acetyl and at
position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6 is
--NH--(CH.sub.2).sub.3-piperazino-(CH.sub.2).sub.3--NH.sub.2.
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the
RGD-peptidomimetic; R'.sub.2 is methoxy; R.sub.4 at position 3 is
acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6
is --NH--(CH.sub.2).sub.2--SO.sub.3K (conjugate 40).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the
RGD-peptidomimetic; R'.sub.2 is methoxy; R.sub.4 at position 3 is
acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6
is --NH--(CH.sub.2).sub.2--SO.sub.3K (conjugate 41).
In another embodiment, R.sub.1 and R.sub.6 together form a cyclic
ring comprising --NH-RGD-CO--NH--(CH.sub.2).sub.2--NH-- or
--NH-RGD-CO--NH--(CH.sub.2).sub.2-piperazino-(CH.sub.2).sub.2--NH--.
In one embodiment, the conjugate comprises a bacteriochlorophyll of
the formula II wherein m is 0; R'.sub.2 is methoxy; R.sub.4 at
position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; and either R.sub.1 and R.sub.6 together form a cyclic ring
comprising --NH-RGD-CO--NH--(CH.sub.2).sub.2--NH-- and M is Pd
(Conjugate 37) or M is 2H (Conjugate 38) or R.sub.1 and R.sub.6
together form a cyclic ring comprising
--NH-RGD-CO--NH--(CH.sub.2).sub.2-piperazino-(CH.sub.2).sub.2--NH--
and M is Pd (Conjugate 39).
In another embodiment, the conjugate comprises a chlorophyll of the
formula II wherein M is 2H; R.sub.1 is NH--P, wherein P is the
residue of the RGD-containing peptide of SEQ ID NO:1; R.sub.4 at
position 3 is vinyl and at position 8 is ethyl; R'.sub.4 is methyl;
and R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate
16).
In another embodiment, the conjugate comprises a chlorophyll of the
formula II wherein M is Mn; R.sub.1 is NH--P, wherein P is the
residue of the RGD-containing peptide of SEQ ID NO:1; R.sub.4 at
position 3 is vinyl and at position 8 is ethyl; R'.sub.4 is methyl;
and R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate
17).
In another embodiment, the conjugate comprises a chlorophyll of the
formula II wherein M is Cu; R.sub.1 is NH--P, wherein P is the
residue of the RGD-containing peptide of SEQ ID NO:1; R.sub.4 at
position 3 is vinyl and at position 8 is ethyl; R'.sub.4 is methyl;
and R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate
18).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula I wherein M is Mn; R.sub.1 is
NH--P, wherein P is the residue of the RGD-containing peptide of
SEQ ID NO:1; R.sub.2 is OH; R.sub.3 is COOCH.sub.3; R.sub.4 at
position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; and R5 is O (Conjugate 12).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula I wherein M is 2H; R.sub.1 is
NH--P, wherein P is the residue of the RGD-containing peptide of
SEQ ID NO:1; R.sub.2 is OH; R.sub.3 is COOCH.sub.3; R.sub.4 at
position 3 is acetyl and at position 8 is ethyl; R'.sub.4 is
methyl; and R5 is O (Conjugate 27).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula I wherein M is 2H; R.sub.1 is
NH--(CH.sub.2).sub.2--NH--CO--P, wherein P is the residue of the
RGD-containing peptide of SEQ ID NO:4; R.sub.2 is OH; R.sub.3 is
COOCH.sub.3; R.sub.4 at position 3 is acetyl and at position 8 is
ethyl; R'.sub.4 is methyl; and R5 is O (Conjugate 32).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO:2; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 11).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is 2H; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO: 1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 13).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Mn; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO: 1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 14).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Cu; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO:1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 15).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO: 1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 24).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO: 1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.3--SO.sub.3K (Conjugate 19).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is 2H; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO:3; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 26).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO:5; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 33).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO:6; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 34).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO:7; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 35).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is Pd; m is 0;
R.sub.1 is NH--CH [(--(CH.sub.2).sub.2--CO--NH--P].sub.2, wherein P
is the residue of the RGD-containing peptide of SEQ ID NO:8;
R'.sub.2 is methoxy; R.sub.4 at position 3 is acetyl and at
position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6 is
--NH--(CH.sub.2).sub.2--SO.sub.3K (Conjugate 36).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is PD; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO: 1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--CH.sub.2--CH(OH)--CH.sub.2OH. (Conjugate 23).
In another embodiment, the conjugate comprises a
bacteriochlorophyll of the formula II wherein M is 2H; m is 0;
R.sub.1 is NH--P, wherein P is the residue of the RGD-containing
peptide of SEQ ID NO: 1; R'.sub.2 is methoxy; R.sub.4 at position 3
is acetyl and at position 8 is ethyl; R'.sub.4 is methyl; and
R.sub.6 is --NH--(CH.sub.2).sub.3--NH--CO-DTPA (Conjugate 43) or
its chelate complex with Gd (Conjugate 44).
The invention further provides the novel bacteriochlorophyll of the
formula II, wherein M is Pd; R.sub.1 is COOH; R'.sub.2 is methoxy;
R.sub.4 at position 3 is acetyl and at position 8 is ethyl;
R'.sub.4 is methyl; and R.sub.6 is
--NH--CH.sub.2--CH(OH)--CH.sub.2--OH (compound 10).
In another aspect, the present invention provides a pharmaceutical
composition comprising a conjugate of an RGD-containing peptide or
an RGD peptidomimetic and a photosensitizer selected from a
porphyrin, a chlorophyll or a bacteriochlorophyll as defined herein
and a pharmaceutically acceptable carrier.
In one embodiment, the pharmaceutical composition comprises a
conjugate comprising a porphyrin photosensitizer as defined herein
or a pharmaceutically acceptable salt thereof. In another
embodiment, it comprises a conjugate comprising a chlorophyll or a
bacteriochlorophyll photosensitizer of formula I, II or III as
defined herein or a pharmaceutically acceptable salt thereof.
In one preferred embodiment the pharmaceutical composition
comprises a conjugate in which the chlorophyll has formula II, more
preferably selected from the conjugates 16, 17 and 18.
In another preferred embodiment the pharmaceutical composition
comprises a conjugate in which the bacteriochlorophyll has the
formula I, more preferably selected from the conjugates 12, 27 and
32.
In another preferred embodiment the pharmaceutical composition
comprises a conjugate in which the bacteriochlorophyll has the
formula III, more preferably the conjugate 19.
In another more preferred embodiment the pharmaceutical composition
comprises a conjugate in which the bacteriochlorophyll has the
formula II conjugated with an RGD peptide, more preferably with the
RGD peptide of SEQ ID NO: 1, more preferably selected from the
conjugates 13, 23, 29, 31, 43, and 44, and more preferably the
conjugate 24.
In another embodiment the pharmaceutical composition comprises a
conjugate in which the bacteriochlorophyll has the formula II
conjugated with an RGD peptide of any of SEQ ID NO:2-8, more
preferably the conjugates 11, 26, 33, 34, 35, and 36.
In another embodiment the pharmaceutical composition comprises a
conjugate in which the bacteriochlorophyll has the formula II
conjugated with an RGD peptidomimetic, more preferably the
conjugates 40 and 41.
In one embodiment, the pharmaceutical composition is for use in
photodynamic therapy (PDT), more particularly for vascular-targeted
PDT (VTP).
In one embodiment, the pharmaceutical composition is for use in
oncology, particularly for VTP of tumors. Any suitable solid tumor
is encompassed by the invention, both primary tumors and
metastasis, of tumors selected from, but not limited to, from
melanoma, colon, breast, lung, prostate, brain or head and neck
cancer.
In another embodiment, the pharmaceutical composition is for use in
non-oncologic diseases, for VTP of non-neoplastic tissue or organ.
In one embodiment, the pharmaceutical composition is used for
treatment of vascular diseases such as age-related macular
degeneration (AMD) or disorders such as obesity by limiting
vascular supply to adipose tissue and thus inhibiting its
growth.
The pharmaceutical composition of the invention is also used for
diagnostic purposes, for visualization of organs and tissues. It
can be used in methods of vascular-targeted imaging (VTI).
In one embodiment, the pharmaceutical composition is used for
diagnosis of tumors using several techniques. Several diagnostic
techniques can be applied in accordance with the invention, by
adapting the central metal atom to the particular technique.
For tumor diagnosis by dynamic fluorescence imaging, M in the
photosensitizer is 2H or a metal selected from Cu, Pd Gd, Pt, Zn,
Al, Eu, Er, Yb or isotopes thereof.
For tumor diagnosis by radiodiagnostic technique, M in the
photosensitizer is a radioisotope selected from .sup.64Cu,
.sup.67Cu, .sup.99mTc, .sup.67Ga, .sup.201Tl, .sup.195Pt,
.sup.60Co, .sup.111In and .sup.51Cr.
In one embodiment, the radiodiagnostic technique is positron
emission tomography (PET) and M is .sup.64Cu or .sup.67Cu. In
another embodiment, the radiodiagnostic technique is single photon
emission tomography (SPET) and M is a radioisotope selected from
.sup.99mTc, .sup.67Ga, .sup.195Pt, .sup.111In, .sup.51Cr and
.sup.60Co.
For tumor diagnosis by molecular magnetic resonance imaging (MRI),
M is a paramagnetic metal selected from Mn.sup.3+, Cu.sup.2+,
Fe.sup.3+, Eu.sup.3+, Gd.sup.3+ and Dy.sup.3+, or the
photosensitizer is substituted by a metal chelate complex of a
polydentate ligand and the metal is as defined hereinbefore.
The present invention also provides a pharmaceutical composition
for tumor radiotherapy, wherein M is a radioisotope selected from
.sup.103Pd, .sup.195Pt, .sup.105Rh, .sup.106Rh, .sup.188Re,
.sup.177Lu, .sup.164Er, .sup.117mSn, .sup.153Sm, .sup.90, .sup.67Cu
and .sup.32P.
The present invention further provides the novel
bacteriochlorophyll of the formula II, wherein M is Pd; R.sub.1 is
COOH; R'.sub.2 is methoxy; R.sub.4 at position 3 is acetyl and at
position 8 is ethyl; R'.sub.4 is methyl; and R.sub.6 is
--NH--CH(OH)--CH.sub.2--OH herein identified as compound 10.
According to one embodiment, the invention relates to a method for
tumor diagnosis by dynamic fluorescence imaging, which comprises:
(a) administering to a subject suspected of having a tumor a RGD
peptide-photosensitizer conjugate of the invention in which M is 2H
or a metal selected from Cu, Pd Gd, Pt, Zn, Al, Eu, Er, Yb or an
isotopes thereof; and (b) irradiating the subject by standard
procedures and measuring the fluorescence of the suspected area,
wherein a higher fluorescence indicates tumor sites.
In another embodiment, the invention provides a method for tumor
diagnosis by radiodiagnostic technique, which comprises: (a)
administering to a subject suspected of having a tumor a RGD
peptide-photosensitizer conjugate of the invention in which M is a
radioisotope selected from .sup.64Cu, .sup.67Cu, .sup.99mTc,
.sup.67Ga, .sup.195Pt, .sup.201Tl, .sup.60Co, .sup.111In or
.sup.51Cr; and (b) scanning the subject in an imaging scanner and
measuring the radiation level of the suspected area, wherein an
enhanced radiation indicates tumor sites. In a preferred
embodiment, the radiodiagnostic technique is positron emission
tomography (PET) and M is .sup.64Cu or .sup.67Cu. In another
preferred embodiment, the radiodiagnostic technique is single
photon emission tomography (SPET) and M is a radioisotope selected
from the group consisting of .sup.99mTc, .sup.67Ga, .sup.195Pt,
.sup.111In, .sup.51Cr and .sup.60Co.
In a further embodiment, the invention provides a molecular
magnetic resonance imaging (MRI) method for tumor diagnosis
comprising the steps of: (a) administering to a subject suspected
of having a tumor a RGD peptide-photosensitizer conjugate of the
invention wherein M is a paramagnetic metal; and (b) subjecting the
patient to magnetic resonance imaging by generating at least one MR
image of the target region of interest within the patient's body
prior to said administration and one or more MR images thereafter.
The paramagnetic metal may be any suitable metal for MRI including,
but not limited to, Mn.sup.3+, Cu.sup.2+, Fe.sup.3+, Eu.sup.3+, or
Dy.sup.3+ and, preferably, Gd.sup.3+.
In one preferred embodiment, the MRI method includes the steps: (a)
administering to the subject a RGD peptide-photosensitizer
conjugate of the invention wherein M is a paramagnetic metal,
preferably, Mn.sup.3+, Cu.sup.2+, Fe.sup.3+, Eu.sup.3+, or
Dy.sup.3+ and, more preferably, Gd.sup.3+; (b) generating an MR
image at zero time and at a second or more time points thereafter;
and (c) processing and analyzing the data to diagnose the presence
or absence of a tumor.
In still another embodiment, the invention provides a method for
diagnosis of tumors by fluorescence imaging using a
photosensitizer, when the improvement is use of a RGD
peptide-photosensitizer conjugate of the invention.
The invention further provides a method for diagnosis of tumors by
PET or SPET scanning using a photosensitizer, when the improvement
is use of a RGD peptide-photosensitizer conjugate of the
invention.
Further provided is a method for diagnosis of tumors by MRI using a
photosensitizer, when the improvement is use of a RGD
peptide-photosensitizer conjugate of the invention.
The RGD peptide-photosensitizer conjugates of the invention are
particularly suitable for vascular-targeting PDT (VTP) and are
useful for treatment of diseases associated with
angiogenesis/neovascularization and new blood vessel growth such as
cancer, diabetic retinopathy, macular degeneration and arthritis.
In one most preferred embodiment of the present invention, the
target for treatment with the sensitizers of the invention are
abnormal blood vessels, particularly blood vessels of solid tumors,
age-related macular degeneration, restenosis, acute inflammation or
atherosclerosis (Dougherty and Levy, 2003), due to the inherent
difference of sensitivity of normal and abnormal blood vessels to
the suggested PDT protocols described herein.
Thus, in one embodiment, the conjugates of the invention are useful
in the oncological field for treatment by PDT of precancerous
states and several cancer types such as, but not limited to,
melanoma, prostate, brain, colon, ovarian, breast, head and neck,
chest wall tumors arising from breast cancer, skin, lung, esophagus
and bladder cancers and tumors. The compounds are useful for
treatment of primary as well as metastatic tumors.
In this aspect, the invention relates to a method for tumor
photodynamic therapy, which comprises: (a) administering to an
individual in need a RGD peptide-photosensitizer conjugate
according to the invention; and (b) irradiating the local of the
tumor.
The invention further relates to tumor therapy without PDT, namely,
to a method for tumor radiotherapy, which comprises administering
to an individual in need a RGD peptide-photosensitizer conjugate
according to the invention wherein M is .sup.103Pd, .sup.195Pt,
.sup.105Rh, .sup.106Rh, .sup.188Re, .sup.177Lu, .sup.164Er,
.sup.117mSn, .sup.153Sm, .sup.90Y, .sup.67Cu, or .sup.32P.
In another embodiment, the compounds of the invention are useful in
non-oncological areas. Besides the efficient destruction of
unwanted cells, like neoplasms and tumors, by PDT, the compounds of
the invention can also be used against proliferating cells and
blood vessels, which are the main cause of arteriosclerosis,
arthritis, psoriasis, obesity and macular degeneration. In
addition, the compounds can be used in the treatment of
non-malignant tumors such as benign prostate hypertrophy.
In one preferred embodiment, the conjugates of the invention can be
used in PDT for treatment of cardiovascular diseases mainly for
vessel occlusion and thrombosis in coronary artery diseases,
intimal hyperplasia, restenosis, and atherosclerotic plaques. In a
more preferred embodiment, the compounds of the invention are used
for preventing or reducing in-stent restenosis in an individual
suffering from a cardiovascular disease that underwent coronary
angiography. In another preferred embodiment, the compounds of the
invention can be used in a method for the treatment of
atherosclerosis by destruction of atheromatous plaque in a diseased
blood vessel.
In another preferred embodiment, the compounds of the invention can
be used in PDT for treatment of dermatological diseases, disorders
and conditions such as acne, acne scarring, psoriasis, athlete's
foot, warts, actinic keratosis, and port-wine stains (malformations
of tiny blood vessels that connect the veins to the arteries
(capillaries) located in the upper levels of the skin).
In another preferred embodiment, the conjugates of the invention
can be used in PDT for treatment of ophthalmic diseases, disorders
and conditions such as corneal and choroidal neovascularization
and, more preferably, age-related macular degeneration (AMD).
The amount of the conjugate to be administered for PDT therapy will
be established by the skilled physician according to the experience
accumulated with porphyrin, Chl and BChl derivatives used in PDT,
and will vary depending on the choice of the derivative used as
active ingredient, the condition to be treated, the mode of
administration, the age and condition of the patient, and the
judgement of the physician.
The wavelength of the irradiating light is preferably chosen to
match the maximum absorbance of the photosensitizer. The suitable
wavelength for any of the compounds can be readily determined from
its absorption spectrum. In a preferred embodiment, a strong light
source is used, more preferably lasers at 720-790 nm when the
photosensitizer is a BChl derivative.
The conjugates of the invention may be further used in photodynamic
therapy as an adjuvant to another current therapy used for the
treatment of a disease, disorder or condition, to make it more
effective. For example, they may be used intraoperatively in
combination with surgery, to help prevent the recurrence of cancer
on large surface areas such as the pleura (lining of the lung) and
the peritoneum (lining of the abdomen), common sites of spread for
some types of cancer, in intraoperative treatment of recurrent head
and neck carcinomas, or following femoral artery angioplasty to
prevent restenosis. The conjugates may be also used in
intraoperative PDT tumor diagnosis, for example, of brain
tumors.
Another possibility according to the invention is to use the
conjugates of the invention in PDT of large solid tumors by
interstitial therapy, a technique that involves feeding optic
fibers directly into tumors using needles guided by computed
tomography (CT). This may be especially useful in areas that
require extensive surgery such as in head and neck tumors.
The amount of conjugate to be administered and the route of
administration will be determined according to the kind of disease,
stage of the disease, age and health conditions of the patient, but
will be much lower than the currently used dosage of Photofrin
II.RTM. (about 5-40 mg HpD/kg body weight) or Tookad.RTM. (about
2-10 mg/kg body weight).
The pharmaceutical compositions of the invention are administered
to the patient by standard procedures used in PDT, for example,
systemically, particularly by injection, more preferably by
intravenous injection, locally by direct injection into the solid
tumor, or topically for treatment of skin diseases and
conditions.
Preferred photosensitizers for the purpose of the present invention
are water-soluble porphyrin, chlorophyll and bacteriochlorophyll
derivatives. The present inventors have previously shown (Mazor et
al, 2005, Brandis et al. 2005) that water-soluble bacteriochlorins
such as WST-11 (herein designated compound 8) circulate as
non-covalent complexes with serum albumin (SA) until clearance, but
despite this association they show no accumulation in the tumor
tissue and rapidly clear from the treated subject.
Insufficient vascularization, linked with enhanced interstitial
fluid pressure due to the lack of lymphatic drainage in the tumor
vicinity, interfere with the convectional uptake of small molecules
used as therapeutic or contrast agents in known diagnostic
protocols, thereby impairing the efficiency of in situ diagnostic
and prognosis techniques such as magnetic resonance imaging (MRI),
blood oxygenation level dependent-MRI, diffusion-weighted MRI and
positron emission tomography (PET). At the same time, enhanced
tumor vascular permeability in these regions drives extravasation
of macromolecules such as serum albumin (SA) from the circulation
into the tumor tissue, while the poor lymphatic drainage fosters
their retention within the tumor compartment (Minchinton and
Tannock, 2006, Iyer et al., 2006). Consequently, the "enhanced
permeability and retention (EPR) effect", has been proposed as the
basis for nonspecific targeting of drugs comprising large molecules
to tumor tissue and has given rise to a new approach for
tumor-targeting drug design based on macromolecular, micellar and
lipidic particles.
In their quest for new imaging avenues, the present inventors found
that small contrast and/or therapeutic agents, such as
water-soluble porphyrin, chlorophyll and bacteriochlorophyll
derivatives designed to have the dual capacity of moderate
association affinity to SA and high affinity to tumor-specific
receptors, would allow for their prolonged accumulation in tumors.
It was assumed that the EPR effect would assist agent extravasation
and retention in the tumor interstitium upon forming a complex with
SA. Once in the tumor tissue, the modified agents will dissociate
from the SA and preferentially bind to specific receptors, ensuring
active agent accumulation. It was found in accordance with the
present invention that by covalent binding of the water-soluble
photosensitizers mentioned above to the RGD-containing peptides and
peptidomimetics, which are ligands of the tumor-abundant cell
receptors integrins, while retaining their SA complexation ability,
contrast and therapeutic agents are obtained that selectively and
synergistically accumulate and retain in the tumor and enable
highly efficient in vivo imaging of such tumors.
The invention will now be illustrated by the following non-limiting
Examples.
EXAMPLES
I Chemical Section
In the Examples herein, the intermediates and compounds 1-10 and
the conjugates of the invention (1-24) will be presented by their
respective Arabic numbers in bold and underlined according to the
following List of Compounds and the Appendix. The formulas of all
the compounds and conjugates are presented in the Appendix at the
end of the description, just before the References.
LIST OF COMPOUNDS
1. Bacteriochlorophyll a (Bchl a) 2.
13.sup.2-OH-Bacteriochlorophyll a (13.sup.2-OH-Bchl a) 3.
Bacteriopheophorbide a (Bpheid a) 4.
13.sup.2-OH-Bacteriopheophorbide a (13.sup.2-OH-Bpheid a) 4a.
Bacteriopurpurin 18 (BPP 18) 5. Chlorophyll a (Chl a) 6.
Pheophorbide a (Pheid a) 7. Palladium Bacteriopheophorbide a
(Pd-Bpheid) 8. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide potassium salt 9. Manganese(III)
13.sup.2-OH-Bacteriopheophorbide a (Mn(III) 13.sup.2-OH-Bpheid a)
10. Palladium
3-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin-13.sup.1-(2-
,3-dihydroxypropyl)amide potassium salt 11. Palladium
3-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(RGD-4C)amide potassium salt
12. Manganese(III)
13.sup.2-OH-Bacteriopheophorbide-17.sup.3-(cycloRGDfK)amide 13.
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt 14. Manganese(III)
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt 15. Copper(II)
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt 16. 3.sup.1,3.sup.2-Didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt 17. Manganese(III) 3.sup.1,3.sup.2-Didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt 18. Copper(II) 3.sup.1,3.sup.2-Didehydrorhodochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt 19. Palladium Bacteriopurpurin
N-(3-sulfopropylamino)imide-17.sup.3-(cycloRGDfK)amide potassium
salt 20.
Meso-5-(4-cycloRGDfK-benzamido)-10,15,20-tris(4-carboxyphenyl)porphine
21. Copper(II)
meso-5-(4-cycloRGDfK-benzamido)-10,15,20-tris(4-carboxyphenyl)
porphine 22. Gadolinium(III)
meso-5-(4-cycloRGDfK-benzamido)-10,15,20-tris(4-carboxy
phenyl)porphine 23. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin-13.sup.1-(2,3-d-
ihydroxypropyl)amide-17.sup.3-(cycloRGDfK)amide 24. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDfK)amide potassium
salt. 25. 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide potassium salt. 26.
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(GRGDSP)amide potassium salt
27. Bacteriopheophorbide-17.sup.3-(cycloRGDfK)amide 28.
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(3-[(3-aminopropyl)amino]propyl)amide-17.sup.3-(cycloRGDfK)amide
29. 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2,3-dihydroxypropyl)amide-17.sup.3-(cycloRGDfK)amide 30.
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-morpholino-N-ethyl)amide-17.sup.3-(cycloRGDfK)amide 31.
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13-{3-[4-(3-aminopropyl)-piperazin-1-yl]-propyl}amide-17.sup.3-(cycloRGDf-
K)amide 32.
Bacteriopheophorbide-17.sup.3-(2-cycloRGDK-amido-N-ethyl)amide 33.
Palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(GRGDSPK)amide potassium salt
34. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[(GRGDSP).sub.4K]amide
potassium salt 35. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRGDf-N(Me)K)amide
potassium salt 36. Palladium
3-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)-17.sup.3-N-[4-heptanedioic acid
bis-(cycloRGDyK-amido)]amide potassium salt 37. Palladium
3-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo(2-RGD-amido-N-ethyl)diamide 38.
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo(2-RGD-amido-N-ethyl)diamide 39. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1,17.sup.3-cyclo{3-[4-(3-aminopropyl-DGR-amido)-piperazin-1-yl]-pr-
opyl}diamide 40. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[4-(methyl-5-(6-guanidino-hexanoyla-
mino)-pentanoic acid)]amide potassium salt 41. Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-[7-amido-3-[[1-(4-guanidino-butyryl-
)-piperidine-3-carbonyl]-amino]-heptanoic acid] potassium salt 42.
Palladium 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide-17.sup.3-(cycloRADfK)amide potassium
salt 43. 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(3-DTPA-amido-N-propyl)amide-17.sup.3-(cycloRGDfK)amide
44. 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(3-Gd-DTPA-amido-N-propyl)amide-17.sup.3-(cycloRGDfK)amide
Materials and Methods
(i) Bacteriochlorophyll a (Bchl a), 1, was obtained as described by
Scherz and Parson, 1984. The procedure started from extraction of
pigments from dry (lyophilized) cells of the photosynthetic
bacteria Rhodovulum sulfidophilum. Purification of the crude
pigment extract was carried out by DEAE-Sepharose column
chromatography according to Omata and Murata, 1983. Briefly,
DEAE-Sepharose was washed with distilled water and then converted
to an acetate form by suspending it in a 1M sodium acetate buffer
(pH=7). The slurry was washed 3 times with acetone and finally
suspended in methanol-acetone (1:3, v:v) for storage at 5.degree.
C. The purity was checked by thin layer chromatography (TLC).
Detailed description of TLC conditions can be found in Fiedor et
al., 1992.
(ii) 13.sup.2-OH-Bacteriochlorophyll a (13.sup.2-OH-Bchl), 2, was
produced by allomerization of Bchl a by stirring a methanol
solution of Bchl a (1 g/ml) in the dark, in contact with air, as
described in Struck et al., 1992.
(iii) Bacteriopheophorbide (Bpheid), 3 and
13.sup.2-OH-Bacteriopheophorbide (13.sup.2-OH-Bpheid) 4, were
synthesized following Wasielewski and Svec, 1980, by
demetallation-deesterification of the corresponding Bchl a or
13.sup.2-OH-Bchl a with 80% aqueous trifluoroacetic acid.
Purification of synthesized Bpheid or 13.sup.2-OH-Bpheid is carried
out on Silica ("Kieselgel 60", Merck, Germany) column with gradient
of methanol in chloroform (0 to 15/25% vol.) as eluent.
(iv) Chlorophyll a (Chl), 5, and (v) Pheophorbide a (Pheid), 6, Chl
was obtained from cyanobacteria Spirulina platensis following the
same routine for obtaining Bchl (see above). Further, Chl is
converted into Pheid following the same procedure as described for
Bpheid above.
(vi) Palladium Bacteriopheophorbide a (Pd-Bpheid a), 7, was
synthesized as described in WO 2000/033833 (Example 2 therein)
(vii) Palladium
3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide potassium salt, 8, was synthesized as
described in WO 2004/045492 (Example 1, synthesis of compound
4).
(viii) 3.sup.1-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin
13.sup.1-(2-sulfoethyl)amide dipotassium salt, 2, was synthesized
by reaction of Bpheid with taurine as described in WO 2004/045492
(Example 2, synthesis of compound 5).
(ix) Bacteriopurpurin 18 (BPP18), 4a was synthesized as described
by Mironov et al., 1992.
(x) The resin, the amino acid derivatives, N-hydroxybenzotriazole
(HOBt) and benzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium
hexafluorophosphate (PyBOP) were purchased from Novabiochem;
N,N-Diisopropylethylamine (DIEA), N,N'-diisopropylcarbodiimide
(DIC) ethylenediamine, 1,4-bis(3-aminopropyl)-piperazine,
1,3-dimethylbarbituric acid (DMBA), diethyldithiocarbamic acid,
sodium salt (DEDTC), 2,2,2-trifluoroethanol (TFE),
triisopropylsilane (TIS), 1,2-ethanedithiol (EDT), trifluoroacetic
acid (TFA), meso-tetra(4-carboxy-phenyl)porphine, sodium
L-ascorbate and 4-oxoheptanedioic acid, were purchased from Aldrich
(USA); N-hydroxysuccinimide (NHS) was purchased from Sigma (USA);
N-hydroxysulfosuccinimide (sulfo-NHS), 1,3-dicyclohexylcarbodiimide
(DCC), N-(3-dimethylaminopropyl)-N-ethyl carbodiimide (EDC),
N-Fmoc-6-aminohexanoic acid,
N.sup..beta.-Fmoc-N.sup..omega.-Boc-.beta.-L-homolysine, and
N-Fmoc-piperidine-3-carboxylic acid were purchased from Fluka
(Switzerland); cadmium acetate, copper acetate and manganese(II)
chloride were from Merck (Germany); and tetrakis
(triphenylphosphine) palladium was obtained from Acros.
Chemicals and solvents of analytical grade were generally used
except when performing HPLC, where HPLC-grade solvents are
applied.
(xi) Peptide Synthesis--
Peptides were synthesized by solid phase methods via Fmoc chemistry
using protected amino acids and cyclicized according to procedures
common in the art. Removal of Fmoc-group and completion of
couplings were monitored by the ninhydrin (Kaiser) test. TFA or a
cocktail solution of TFA/thioanisole/H.sub.2O/triisopropylsilane
(TIS) was used for peptide removal from the resin simultaneously
with deprotection (Arg-pentamethylchroman-6-ylsulfonyl (Pmc) or
2,2,4,6,7-pentamethyldihydro benzofuran-5-sulfonyl (Pbf); Asp-OtBu;
Ser-tert-butyl (tBu); Lys-tert-butyloxycarbonyl (Boc),
allyloxycarbonyl (Alloc) or Dde).
(i) Linear peptides GRGDSPK, (GRGDSP).sub.4K or GRGDSP were
obtained using Fmoc-Lys(Boc)-Wang resin or 2-chlorotrityl chloride
resin, respectively.
(ii) Cyclic peptides (cycloRGDfK), (cycloRGDyK), (cycloRADfK) and
(cycloRGDf-N(Me)K) were prepared by synthesis of pentapeptides on
2-chlorotrityl chloride resin and their subsequent cyclization in
solution as described in Haubner et al., 1999. N.sup..alpha.-methyl
protected lysine was prepared from 2-aminoheptanedioic acid as
described previously (Freidinger et al., 1983). Another method of
synthesis of cycloRGDfK by cyclization on the resin is described in
Example 13 herein.
(iii) Cyclic peptide RGD-4C was prepared by synthesis of CDCRGDCFCG
by standard solid phase synthesis protocol and its cyclicization by
spontaneous oxidative formation of disulfide bonds (Koivunen et al.
1995).
(iv) Cyclic peptidyl-amine cycloRGDK-NH.sub.2 was synthesized on
chlorotrityl-resin (protections: Arg-Pbf; Asp-OtBu;
N.sup..epsilon.-Lys-Alloc). Then, N-terminal Fmoc group and the
Alloc protecting group on the .epsilon.-amino of the lysine residue
were cleaved, and the cyclization between the two aminos through an
urea bond using N,N'-carbonyldiimidazole (CDI) was allowed for
12-16 h. The cyclic peptide was cleaved from the support and the
lysine carboxylate was reacted with 1,2-diaminoethane (DCC
activation) to obtain the required peptidylamine.
(v) Cyclopeptide dimer (cycloRGDyK).sub.2. 4-Oxoheptanedioic acid
was converted into 4-aminoheptanedioic acid according to Wanunu et
al., 2005. Then the amino group was Boc-protected and carboxylic
moieties were activated with NHS/DCC in DMF. The diester was
purified on silica column with chloroform-methanol, and then
reacted with cycloRGDyK in DMF containing DIEA overnight. The Boc
protection was cleaved with TFA-water-dichloromethane (DCM)
(90:5:5). The desired compound was purified by HPLC.
(vi) RGD-Peptidomimetics (RGD-PM1, RGD-PM2) were obtained according
to WO 93/09795. Namely, one amino group of ethyl
5-amino-4-aminomethyl)pentanoic acid (Vaillancourt et al. 2001 and
refs therein) was protected with equimolar amount of Boc anhydride
and the carboxylic group was protected with tert-butyl alcohol. The
product was purified on silica column, and coupled with
N-Fmoc-6-aminohexanoic acid followed by Fmoc-deprotection and
conversion of the amine to guanidinium with 3,5-dimethylpyrazole
1-carboxamidine nitrate (pH 9.5; 50.degree. C.). Finally, the N-Boc
and O-tBu were removed with TFA, and the product RGD-PM1 was
purified by HPLC. The synthesis of RDG-PM1 is depicted in Scheme 3.
For the synthesis of RGD-PM2 (see Scheme 3),
N.sup..beta.-Fmoc-N.sup..omega.-Boc-3-L-homolysine was attached to
Wang-resin. Next, couplings with N-Fmoc-piperidine-3-carboxylic
acid and N-Fmoc-4-aminobutyric acid were performed using solid
phase methods. After guanidinium formation (as described above),
the resulting material was deprotected and removed from the resin
with TFA, and the product RGD-PM2 was purified by HPLC.
(xii) TLC: silica plates (Kieselgel-60, Merck, Germany);
chloroform-methanol (4:1, v/v).
(xiii) The extinction coefficients of the metallocomplexes were
determined by correlating the central metal concentration (using
flame photometry with metal salt as a standard) with the optical
density of the examined solution at the particular wavelength.
(xiv) Mass spectra. Electrospray ionization mass spectra (ESI-MS)
were recorded on a platform LCZ spectrometer (Micromass, England).
The Matrix-assisted laser desorption/ionization mass spectra
(MALDI-TOF-MS) measurements were performed on Bruker REFLEX
time-of-flight instrument (Bruker Daltonics, USA).
(xv) Optical absorption (UV-VIS) spectra of the different complexes
were recorded with either Genesis-2 (Milton Roy, England), V-570
(JASCO, Japan) or Shimadzu UV-1650PC (Japan)
spectrophotometers.
(xvi) HPLC was performed using an LC-900 instrument (JASCO, Japan)
equipped with a UV-915 diode-array detector, or a Waters Delta Prep
4000 system equipped with a Waters 486 UV-VIS tunable absorbance
detector and a Waters fraction collector, controlled by Millennium
v3.05 program. The flow rate was set to 75 ml/min, using a
preparative column (Vydac C18, 218TP101550, 50.times.250 mm, 10-15
m), the detector was set at wavelength 380 nm and the fraction
collector was set at a time mode of 6 s/fraction. Solvents used in
the HPLC purification were as follows: solvent A: 50 mM solution of
ammonium acetate in H.sub.2O; solvent B: acetonitrile.
(xvii) LC-MS API 150EX (Applied Biosystems/MDS SCIEX), was
performed using YMS-Pack Pro C18 column. Mobile phase: solvent A:
0.2% AcOH/0.12% NH.sub.4OH/H.sub.2O; solvent B: 4.75% A/0.2%
AcOH/acetonitrile. Flow rate: 200 l/min. Gradient: 20% B(0-2 min)
to 95% B(25-30 min).
Example 1. Synthesis of Conjugate 11
Compound 8, obtained as described in Material and Methods, was
directly conjugated to the cyclic peptide RGD-4C as described in
Scheme 1 as follows: compound 8 (10 mg) was reacted overnight with
NHS (20 mg) in the presence of EDC (20 mg) in DMSO (3 ml). The
obtained activated succinimide ester (Bauminger and Wilchek, 1980)
was purified on a silica column using CHCl.sub.3:MeOH (6:1, vol.),
dried and kept under argon in the dark until further use. RGD-4C (2
mg, 1.97 moles) was dissolved in 800 .mu.l DMSO and added to the
activated ester (4.8 mg, 5.13 moles in 800 .mu.l DMSO and 400 .mu.l
NaHCO.sub.3 buffer 0.1 M pH 8.5). The reaction mixture was
incubated at room temperature for 24 hours, and stirred under
argon. The obtained conjugate 11 was purified using HPLC and
identified by mass spectroscopy (1837 m/z) (FIGS. 1A-1C). Yield:
18%.
Example 2. Synthesis of Conjugate 12
Conjugate 12 was prepared starting from the synthesis of compound
9.
(i) Synthesis of Compound 9
Compound 4 (20 mg), obtained as described in Materials and Methods,
was dissolved in DMF (8 ml) that was previously passed through
Alumina B column (1.times.5 cm), and bubbled with Argon for 5-10
minutes. Cadmium acetate (85 mg, 10 eq. to 4) was added and the
reaction mixture heated to 110.degree. C. The reaction progress was
monitored spectrally (in acetone). Metalation occurred within 5
minutes. MnCl.sub.2.2H.sub.2O (55 mg, 10 eq.) was added while
stirring until the reaction was completed (within additional 5-10
minutes). To remove inorganic salts, the reaction solution was
evaporated; the solid was re-dissolved in acetonitrile, the
solution was filtered through Whatman paper on Buchner funnel and
evaporated. Finally, HPLC of the crude product re-dissolved in
water was performed (LC-900 instrument, JASCO, Japan; column
S10P-.mu.m ODS-A 250.times.20 mm, YMC, Japan) with 50% aqueous
acetonitrile as a mobile phase at a flow of 8 ml/min, and the pure
product 9 was eluted at 10.5-13.5 min., providing a full separation
of the product from chlorin admixtures and by-products. Yield:
88%.
The structure of compound 9 was confirmed spectrally (see
electronic spectrum depicted in FIG. 2A) and by mass spectrum (FIG.
2B, ESI-MS, positive mode and also negative mode to check for the
absence of MnCl.sub.2; 679 m/z).
(ii) Synthesis of Conjugate 12
Compound 9 (15 mg) was dissolved in DMSO with sulfo-NHS (30 mg) and
DCC (24 mg), the reaction mixture was stirred at room temperature
under argon atmosphere overnight, evaporated, re-dissolved in 5 mM
phosphate buffer pH 8.0 (1.5 ml) and filtered. CycloRGDfK (30 mg)
in DMSO (2.5 ml) was added to the filtrate, the mixture was stirred
under argon atmosphere for 6 hrs, evaporated, re-dissolved in water
(2 ml), and purified on HPLC on preparative C.sub.18 column using a
gradient elution of acetonitrile in water, 10-40%, during 15 min.,
flow 7 ml/min. The purified conjugate 12 was dried under reduced
pressure and stored at -20.degree. C. under argon atmosphere till
application.
Example 3. Synthesis of Conjugate 14
The title compound was prepared starting from the synthesis of the
unmetalated conjugate 13, as follows.
(i) Synthesis of Conjugate 13
Bpheid (compound 3) (40 mg), prepared as described in Materials and
Methods above, was activated with NHS (80 mg) and DCC (60 mg) in
chloroform (5 ml) under stirring, at room temperature overnight.
The obtained activated ester was purified on silica column using
chloroform as eluent, and then reacted with cycloRGDfK (40 mg) in
DMSO (5 ml) under stirring and argon atmosphere overnight. Then,
taurine (50 mg) dissolved in 1M dipotassium hydrogen phosphate (1.5
ml, pH adjusted to 8.2) was added to the reaction, and the mixture
was evaporated, leading to the putative compound 13. The product
was purified by HPLC on reversed phase using gradient elution with
5 mM phosphate buffer, pH 8.0, and methanol, as described
previously (Brandis et al., 2005). Yield: 52%.
(ii) Synthesis of Conjugate 14
Manganese was inserted into compound 13 using the procedure
employed in Example 2. The product, conjugate 14, was purified by
HPLC using gradient elution with acetonitrile and water as
described previously (Brandis et al., 2005).
Example 4. Synthesis of Conjugate 15
An aqueous solution of copper acetate (2 mg) was added to a mixture
of conjugate 13 (3 mg) (prepared in Example 3 (i)) and sodium
ascorbate (2 mg) in water. The reaction was immediately monitored
by spectrophotometry. After copper insertion into the macrocycle,
the product was purified on a RP-18 cartridge (Lichrolut, Merck),
first using water to wash out non-reacted copper acetate and
ascorbates, and then methanol for the elution of the main compound,
conjugate 15, which was collected and evaporated. Yield: 86%.
For the preparation of radioactive conjugates, the same procedure
is used with water-soluble salts other than acetate of
freshly-prepared radioactive isotope .sup.64Cu or .sup.67Cu (t1/2
is 12.70 h and 2.58 d, respectively).
Example 5. Synthesis of Conjugate 17
The title compound was prepared starting from the preparation of
the unmetalated conjugate 16.
(i) Synthesis of Conjugate 16
Conjugate 16 was prepared as in Example 3(i), but using Pheid
(compound 6) as the starting material instead of Bpheid.
(ii) Synthesis of Conjugate 17
Conjugate 17 was synthesized according to the procedure described
in Example 3(ii), using conjugate 16 obtained above as the starting
material.
Example 6. Synthesis of Conjugate 18
The title compound was synthesized following the procedure of
Example 5 above, using compound 16 as the starting material.
Example 7. Synthesis of Conjugate 19
The preparation of conjugate 19 is schematically described in
Scheme 2 hereinafter.
Bacteriopurpurin 18 (BPP 18), 4a (20 mg) obtained as described in
Materials and Methods, and palladium acetate (10 mg) in chloroform
(8 ml) were mixed with palmitoyl ascorbate (25 mg) in methanol (12
ml). After 20 min. of stirring, the reaction was completed
(monitoring was carried out by spectrophotometry), and the mixture
was shaken with chloroform/water. The organic layer was collected,
dried over sodium sulfate, evaporated, and purified on silica
column with chloroform-acetone elution, to obtain Pd-BPP 18. UV-VIS
Spectrum: 342, 414, 534 and 810 nm in chloroform.
Pd-BPP 18 (18 mg) was stirred with hydrazine hydrate (12 .mu.l) in
pyridine (8 ml) for 35 min, the reaction mixture was poured into
chloroform (30 ml) and 1N HCl (30 ml), and stirred for additional 2
hrs. Then, the organic layer was dried over sodium sulfate, propane
sultone (50 mg) was added, and the mixture stirred for 10 min. and
evaporated. The residue was treated with aqueous ammonia (28%, 3
ml) for 30 min. to eliminate unreacted sultone by conversion into
sulfopropylamine, and the mixture was evaporated again. Water (3
ml) was added to dissolve the residue and the product was purified
on a RP-18 cartridge (Lichrolut, Merck), first using water to wash
out sulfopropylamine, and then methanol for the elution of the main
compound, thus obtaining
Pd-Bacteriopurpurin-N-(3-sulfopropylamino)imide (UV-VIS Spectrum:
344, 417, 528 and 822 nm in water).
Pd-Bacteriopurpurin-N-(3-sulfopropylamino)imide (10 mg) was reacted
overnight with NHS (20 mg), in the presence of EDC (20 mg) in DMSO
(3 ml). The obtained activated ester was purified on a silica
column using CHCl.sub.3:MeOH (5:1), dried and kept under argon in
the dark until further use.
CycloRGDfK (5 mg) was dissolved in 1 ml of DMSO, added to the
activated complex (5 mg) in 1 ml of DMSO, and the reaction mixture
was incubated at room temperature for 24 hours, and stirred under
argon. The obtained conjugate 19 was purified using HPLC, and
identified by mass spectroscopy (ESI-MS positive mode, 1415
m/z).
Example 8. Synthesis of Conjugate 21
The title compound was prepared starting from the synthesis of
conjugate 20 as follows.
(i) Synthesis of Conjugate 20
Meso-tetra(4-carboxyphenyl)porphine (20 mg, 25 .mu.mol), was mixed
with sulfo-NHS (4 mg, 36 .mu.mol) and EDC (6 mg, 30 .mu.mol) in
DMSO (6 ml), and stirred at room temperature for 24 hr. Then,
cycloRGDfK (20 mg, 33 .mu.mol) was added, the reaction mixture was
stirred for further 24 hr, and then evaporated to dryness,
re-dissolved in water and purified on HPLC on preparative C.sub.18
column, using a gradient elution of acetonitrile in 0.2% acetic
acid 30-50% during 15 min., flow 6 ml/min. The purified conjugate
20 was dried under reduced pressure and stored at -20.degree.
C.
(ii) Synthesis of Conjugate 21
Conjugate 20 (4 mg) was dissolved in 50%-aqueous methanol and
aqueous solutions of copper acetate (2 mg) and sodium ascorbate (2
mg) were added. The reaction was completed in 2 min. (monitored by
spectrophotometry). The product was purified on RP-18 cartridge
(Lichrolut, Merck), first, using water to wash out unreacted copper
acetate and ascorbate, and then methanol for the elution of the
main compound, conjugate 21, which is collected and evaporated
(UV-VIS Spectrum: 418 and 538 nm in water).
Example 9. Synthesis of Conjugate 22
Conjugate 20 (4 mg), obtained in Example 8(i) above, and gadolinium
acetylacetonate (10 mg) were heated in imidazole (0.3 g) at
210.degree. C., as previously described (Horrocks et al., 1978).
The reaction was completed in 50 min. (monitored by
spectrophotometry). After sublimation of imidazole, the product was
re-dissolved in water and purified on HPLC, as described in Example
8(i).
Example 10. Synthesis of Conjugate 23
Conjugate 23 was prepared starting from the synthesis of compound
10.
(i) Synthesis of Compound 10
Pd-Bpheid a (compound 7) (100 mg) was dissolved in
N-methylpyrrolidone (1 ml) and 3-amino-2-propanediol (405 mg) and
the solution was mixed during 3 hours at room temperature under
argon atmosphere. The product 10 was purified on HPLC using YMC-C18
preparative column with 0.2% acetic acid/acetonitrile. Yield: 86%.
Analysis was performed on LC-MS using YMC-C18 analytical column
with ammonium acetate, pH 4.5/acetonitrile. ESI-MS positive mode,
805 m/z.
(ii) Synthesis of Conjugate 23
Compound 10 (50 mg), NHS (80 mg) and DCC (216 mg) were dissolved in
dry N,N-dimethylformamide (8 ml). The solution was stirred for 90
min at room temperature under argon atmosphere. The active ester
formed was purified on HPLC using YMC-C18 preparative column with
0.2% acetic acid/acetonitrile, analyzed on LC-MS using YMC-C18
analytical column with ammonium acetate, pH 4.5/acetonitrile, and
identified by mass spectroscopy: ESI-MS positive mode, 902 m/z.
The active ester (10 mg) was dissolved in dry N-methylpyrrolidone
(1 ml). CycloRGDfK (8 mg) and triethylamine (10 .mu.l) were added
and the solution was stirred for 75 min. The product was purified
on HPLC using YMC-C18 preparative column with 0.2% acetic
acid/acetonitrile. Yield: 50%. Analysis was performed on LC-MS
using YMC-C18 analytical column with ammonium acetate pH
4.5/acetonitrile: ESI-MS positive mode, 1393 m/z.
Example 11. Synthesis of Conjugate 24
Compound 8 (100 mg) was activated with NHS (70 mg) and
N-cyclohexylcarbodiimide-N'-methyl polystyrene (120 mg) in DMF (5
ml). The solution was stirred at 50.degree. C. during 15 hours and
filtered through a sinter glass. CycloRGDfK (100 mg) was dissolved
in DMF (5 ml) containing N-methylmorpholine (100 .mu.l) and added
to the filtrate. The mixture was stirred under argon atmosphere at
room temperature for 24 hours, the solvent was evaporated in
vacuum, and the product 24 was purified on HPLC using YMC-C18
preparative column with ammonium acetate pH 4.5/acetonitrile.
Yield: 23%. Analysis was performed on LC-MS with YMC-C18 analytical
column under the same conditions. UV-VIS spectrum (HPLC): 332, 386,
516, and 750 nm. ESI-MS positive mode, 1425 m/z.
Example 12. Synthesis of Conjugate 26
To the Fmoc-deprotected GRGDSP-resin (0.35 mmol), a mixture of
compound 25 (530 mg, 0.7 mmol), HOBt, PyBOP (both 0.7 mmol) and
DIEA (2.1 mmol) in 6 ml of DMF was added, and the reaction was
agitated during 2 h under argon atmosphere. After washings with DMF
(10.times.5 ml) and DCM (5.times.5 ml), the resin was dried in
vacuum for at least 3 h. The peptide-conjugate was then cleaved
from the resin and deprotected (Arg, Pbf; Asp, OtBu) using a
cocktail solution of 85:5:5:5
TFA/thioanisole/H.sub.2O/triisopropylsilane (TIS) (10 ml) for 10
min at 0.degree. C. and then 1 h at room temperature under Ar
atmosphere. The resin was filtered and washed with the cocktail
solution (4 ml) and the combined filtrate was evaporated by a
stream of N.sub.2 to about half of its volume. Upon addition of
cold Et.sub.2O (30 ml), a dark precipitate appeared. Centrifugation
and decantation of the Et.sub.2O layer and additional treatment
with cold Et.sub.2O (2.times.30 ml) afforded the crude dark solid,
which was further purified by RP-HPLC (264 mg; 58%). Analysis was
performed on LC-MS using YMC-C18 analytical column with ammonium
acetate pH 4.5/acetonitrile: ESI-MS positive mode, 1306 m/z.
Example 13. Synthesis of Conjugates 28-31
The title compounds were prepared starting from the synthesis of
the unmetalated Bpheid-cycloRGDfK conjugate 27, as follows.
(i) Solid Phase Synthesis of cycloRGDfK
Fmoc-C.sup..alpha.-allyl protected aspartic acid was attached on
2-chlorotrityl chloride resin. Next, glycine, N.sup.G-Pbf arginine,
N.sup..epsilon.-Dde lysine, and phenylalanine were attached on the
resin by usual Fmoc chemistry, forming fKRGD peptidyl-resin. Then,
the N-terminal Fmoc group was removed with 2%-piperidine/DMF, and
the C.sup..alpha.-allyl group on aspartic acid residue was removed
with tetrakis(triphenylphosphine) palladium and
1,3-dimethylbarbituric acid (DMBA) in DCM. The peptide was cyclized
in the presence of HOBt/PyBOP and DIEA. The .epsilon.-amine of the
lysine residue was cleaved with 4%-hydrazine/DMF.
(ii) Synthesis of Conjugate 27
Bpheid (3, 0.6 mmol) was bound to .epsilon.--NH.sub.2-Lys on the
fKRGD peptidyl-resin (0.3 mmol) in DMF using PyBOP/HOBt (0.6 mmol)
as coupling agents and DIEA (1.8 mmol) as a base, thus obtaining
conjugate 27.
(iii) Synthesis of Conjugates 28-31
Conjugate 27 (0.1 mmol) was treated on the resin with the
appropriate amine in Table 1 (5-6 mmol) in DMF at room temperature
during 2 h. Then, the amine excess was washed off, the product was
disconnected from the resin, deprotected with the TFA-containing
cocktail, and finally purified by RP-HPLC. Analysis was performed
on LC-MS using YMC-C18 analytical column with ammonium acetate pH
4.5/acetonitrile. The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Yield and ESI-MS of Conjugates 28-31 Yield,
mg ESI-MS (+), Conjugate Amine (%) m/z 28 bis(3-aminopropyl)amine
71 (53) 1327 29 3-amino-1,2-propanediol 63 (49) 1287 30
N-(2-aminoethyl)morpholine 75 (56) 1326 31
1,4-bis(3-aminopropyl)piperazine 75 (54) 1396
Example 14. Synthesis of Conjugate 32
Conjugate 32 was obtained by coupling peptidylamine
cycloRGDK-NH.sub.2 (obtained as described in Material and Methods)
and Bpheid a (3) in DMF solution in the presence of DCC, followed
by Pbf and O-tBu deprotection with TFA. The product was purified by
RP-HPLC. Yield: 53%. Analysis was performed on LC-MS using YMC-C18
analytical column with ammonium acetate pH 4.5/acetonitrile: ESI-MS
positive mode, 1135 m/z.
Example 15. Synthesis of Conjugate 33
Conjugate 33 was obtained by conjugating compound 8 with the linear
peptide GRGDSPK (obtained as described in Material and Methods)
similarly to the method described for conjugate 24 in Example 11.
Yield: 55%. Analysis was performed on LC-MS using YMC-C18
analytical column with ammonium acetate pH 4.5/acetonitrile: ESI-MS
positive mode, 1537 m/z.
Example 16. Synthesis of Conjugate 34
Conjugate 34 was obtained by conjugating compound 8 with the linear
peptide (GRGDSP).sub.4K (obtained as described in Material and
Methods) similarly to the method described for conjugate 24 in
Example 11. Yield: 41%. Analysis was performed on LC-MS using
YMC-C18 analytical column with ammonium acetate pH
4.5/acetonitrile. MALDI-MS positive mode, 3291 (M+2Na) m/z.
Example 17. Synthesis of Conjugate 35
Conjugate 35 was obtained by conjugating compound 8 with
cycloRGDf-N(Me)K (obtained as described in Material and Methods)
similarly to the method described for conjugate 24 in Example 11.
Yield: 58%. Analysis was performed on LC-MS using YMC-C18
analytical column with ammonium acetate pH 4.5/acetonitrile: ESI-MS
positive mode, 1439 m/z.
Example 18. Synthesis of Conjugate 36
Conjugate 36 was obtained by conjugating compound 8 with the cyclic
dimer peptide (cycloRGDyK).sub.2 (obtained as described in Material
and Methods) similarly to the method described for conjugate 24 in
Example 11. Yield: 27%. Analysis was performed on LC-MS using
YMC-C18 analytical column with ammonium acetate pH
4.5/acetonitrile. MALDI-MS positive mode, 2245 (M+2Na) m/z.
Example 19. Synthesis of Conjugate 37
The conjugate 37 was synthesized from Pd-Bpheid (compound 7) and
the peptide RGD. The peptide was prepared by the solid phase
procedure by coupling of Fmoc-Arg (Pbf)-Gly-OH to a resin bound
H-Asp-O-Allyl residue.
(i) Preparation of Protected Dipeptide Arg-Gly
A solution of Fmoc-Gly-OH (4.162 g; 14 mmol) and DIEA (9.755 g; 56
mmol) in 100 ml of dry DCM was stirred with 10 g of 2-chlorotrityl
chloride resin (1.4 mmol/g) for 1 h at room temperature (rt). The
Fmoc group was removed by treatment with 5% piperidine in DMF/DCM
(1:1), followed by 20% piperidine in DMF. Then, Fmoc-Arg (Pbf)-OH
(18.17 g; 28 mmol) in DMF (130 ml) was activated with HOBt (4.29 g;
28 mmol) and DIC (4.34 ml; 28 mmol) for 15 min at rt and added to
the reaction vessel. The mixture was stirred for 2 h at rt. The
peptidyl-resin was washed and dried in vacuum for 3 h. The
protected dipeptide was cleaved from the resin by stirring with a
cocktail solution of AcOH/2,2,2-trifluoroethanol (TFE)/DCM (1:1:3)
for 1 h at rt. Upon treatment with cold Et.sub.2O (1 l), the oily
residue solidified. Filtration and washings with cold Et.sub.2O
afforded the white precipitate (8.64 g; 87.5%) with homogeneity of
about 99% (HPLC).
(ii) Synthesis of the Tripeptide RGD
Attachment of the third amino acid to the dipeptide obtained in
step (i) above started by stirring 2-chlorotrityl chloride resin
(0.5 g; 1.4 mmol/g) with a solution of Fmoc-Asp-O-Allyl (138.4 mg;
0.35 mmol) and DIEA (244 .mu.l; 1.4 mmol) in DCM during 1 h at rt
to give a loading of about 0.7 mmol/g. Then, the resin was washed
and Fmoc was removed as described above. Fmoc-Arg (Pbf)-Gly-OH (371
mg; 0.525 mmol), HOBt (80.4 mg; 0.525 mmol) and DIC (81 .mu.l;
0.525 mmol) were dissolved in 2.5 ml DMF and stirred at rt for 20
min. The resulting solution was added to the washed
H-Asp-O-Allyl-resin, and the mixture was agitated for 2 h at rt.
The peptidyl-resin was washed, and Fmoc was removed.
(iii) Synthesis of Conjugate 37
A mixture of compound 7 (268 mg; 0.375 mmol), HOBT (57.4 mg; 0.375
mmol) and DIC (58 .mu.l; 0.375 mmol) in 3 ml of DMF was stirred for
30 min at rt and added to an aliquot of Fmoc-deprotected
tripeptidyl-resin obtained in (ii) above (about 0.125 mmol). The
mixture was agitated for 2 h at rt, and the conjugate of 7 with the
linear tripeptide RGD was obtained. This reaction and all following
operations with modified peptidyl-resin were performed in Argon
atmosphere in the dark. After washing, the resin was treated with
ethylenediamine (251 .mu.l; 375 mmol) in DMF during 1 h at rt, then
washed. In order to remove the allyl-protecting group, the resin
was reacted with a solution of
[(C.sub.6H.sub.5).sub.3P].sub.4Pd.sup.0 (87 mg; 0.075 mmol) and
DMBA (137 mg; 0.875 mmol) in DCM during 2 h at rt.
On-resin cyclization was accomplished by binding the deprotected
Asp residue to the ethylenediamino moiety using a solution of PyBOP
(195 mg; 0.375 mmol) and DIEA (131 .mu.l; 0.75 mmol) in DMF for 2 h
at rt. The resin was washed and dried in vacuum for 3 h. The
peptide conjugate was cleaved from the resin using a cocktail
solution TFA/Thioanisole/H.sub.2O/TIS/EDT (82.5:5:5:5:2.5) for 10
min at 0.degree. C. and then 1 h at rt. Upon the addition of cold
Et.sub.2O (25 ml), a dark solid was obtained. The crude product (95
mg) was purified by RP-HPLC to give 2 mg of pure (98%) cyclic RGD
conjugate 37. ESI-MS 1087 (M+H) m/z.
Example 20. Synthesis of Conjugate 38
The synthesis was carried out on a 0.175 mmol scale using the same
procedure as described in Example 19, but starting from the
compound Bpheid 3 instead of Pd-Bpheid 7. The crude product (160
mg) was purified by RP-HPLC to give 17 mg of pure (98%) cyclic RGD
conjugate 38. ESI-MS 982 (M+H) m/z.
Example 21. Synthesis of Conjugate 39
The procedure is similar as in Example 19, but
1,4-bis(3-aminopropyl)-piperazine was used for "bridge"-formation
between the Bpheid residue and the Asp-residue instead of
ethylenediamine. The crude product (158 mg) was purified by RP-HPLC
to give 12.5 mg of pure (99%) cyclic RGD conjugate 39. ESI-MS 1122
(M+H) m/z.
Example 22. Synthesis of Conjugate 40
Conjugate 40 was obtained by a method similar to that described for
conjugate 24, but using the linear RGD-peptidomimetic
5-(6-guanidino-hexanoylamino)-pentanoic acid (RGD-PM1). Yield: 42%.
Analysis was performed on LC-MS using YMC-C18 analytical column
with ammonium acetate pH 4.5/acetonitrile: ESI-MS positive mode,
1123 m/z.
Example 23. Synthesis of Conjugate 41
Conjugate 41 was obtained by a method similar to that described for
conjugate 24, but using the linear RGD-peptidomimetic
1-(4-guanidino-butyryl)-piperidine-3-carbonyl]-amino]-heptanoic
acid (RGD-PM2). Yield: 66%. Analysis was performed on LC-MS using
YMC-C18 analytical column with ammonium acetate pH
4.5/acetonitrile: ESI-MS positive mode, 1220 m/z.
Example 24. Synthesis of Conjugate 42
Conjugate 42 was obtained by a method similar to that described for
conjugate 24 in Example 11, but using the peptide cycloRADfK.
Yield: 30%. Analysis was performed on LC-MS using YMC-C18
analytical column with ammonium acetate pH 4.5/acetonitrile: ESI-MS
positive mode, 1439 m/z.
Example 25. Synthesis of Conjugate 43
The title compound was prepared starting from the synthesis of the
Bacteriopheophorbide-17.sup.3-(cycloRGDfK)amide conjugate 27, as
described in Example 13.
Conjugate 27 (0.1 mmol) was treated on the resin with an
1,3-propylene diamine (6 mmol) in DMF at room temperature during 2
h. Then, the amine excess was washed off, and DTPA dianhydride (0.2
mmol) and triethylamine (100 ml) in anhydrous DMF (30 ml) was
added. After 1-h agitation under argon atmosphere, distilled water
(50 ml) was added, followed by additional agitation for 30 min. The
product 43 was disconnected from the resin, deprotected with the
TFA-containing cocktail, and finally purified by RP-HPLC (61 mg,
37%). Analysis was performed on LC-MS using YMC-C18 analytical
column with water/acetonitrile. ESI-MS negative mode, 1643 m/z.
Example 26. Synthesis of Conjugate 44
Gadolinimum chloride (0.1 mmol) in a sodium acetate buffered
aqueous solution (0.1 N, pH 5.5) was added into a solution of
conjugate 43 (6 .mu.mol) in 2 mL of DMF. The mixture was allowed to
stand at ambient temperature for overnight with stirring. The
formation of the metal chelates was verified by LC-MS (1799 m/z).
The reaction mixture was evaporated, and the product was purified
on a RP-18 cartridge (Lichrolut, Merck), first using water to wash
out non-reacted gadolinium salt, and then methanol for the elution
of the main compound, conjugate 44, which was collected and
evaporated (8 mg, 73%).
I. Biological Section
Materials and Methods
(i) Eu-Labeled RGD-4C.
RGD-4C (20 nmole in 10 .mu.l DDW) was added to 100 .mu.l of
K-phosphate buffer (0.1 M, pH 8.5) containing
isothiocyanatophenyl-DTPA-Eu (150 nmole, 50 .mu.l). The mixture was
incubated overnight at room temperature with constant stirring. To
terminate the reaction, 1 .mu.l of Tris-Cl (1 M, pH 7.5) was added,
the mixture was stirred for 5 min, then loaded on Sep-Pak C-18
cartridge and washed with DDW to elute the free Eu. The column was
then washed with 50% aqueous ethanol, fractions (250-500 .mu.l)
were collected and their fluorescence measured.
(ii) Covalent Attachment to Human Serum Albumin (HSA).
HSA (90 mg) was activated with sulfoNHS and
1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC)
(sulfoNHS:EDAC:HSA=1000:500:1 molar ratio) in 50 mM phosphate
buffer, pH 5.0. After 45 minutes, a sample of the reaction mixture
(about 1 ml) was passed through PD-10 column (Sephadex G-25M, GE
Healthcare, Uppsala, Sweden) using 5 ml of the same buffer to
recover the protein fraction (HSA-sNHS). Photosensitizers,
conjugated or non-conjugated to RGD-containing peptide (about 20 mg
each), were dissolved in DMF (2 ml) and added to 2 ml HSA-sNHS,
diluted with 4 ml of 50 mM phosphate buffer, pH 8.0, and 1 ml of 5%
mannitol. Reaction mixtures were sonicated and stirred overnight
under argon atmosphere, then evaporated to remove DMF, re-dissolved
in water and passed again through PD-10 column for collection of
photosensitizer-HSA-conjugates. To remove non-covalently bound
photosensitizers, the products were evaporated and extracted
several times with methanol. The extent of HSA conjugation was
calculated from the molar ratios between the photosensitizer and
HSA parts, determined spectrophotometrically and by Bradford assay,
respectively. Approximately 10% of HSA was conjugated. Aliquots of
conjugates equal to 0.7 nmol photosensitizer, were prepared for
injections.
(iii) Association Constants of Photosensitizers to HSA.
Association constants of photosensitizers, conjugated or
non-conjugated to an RGD-containing peptide, were deduced from
spectroscopic measurements of the ratio between the photosensitizer
and HSA for different concentrations of HSA using both factor
analysis, as previously described (Brandis et al., 2005) and by
monitoring changes in the near infrared (NIR) absorption of the
photosensitizers during titration with HSA. Briefly, all
photosensitizers (PhSs) present broad NIR absorption with reduced
intensity in SA-free aqueous solutions. Upon addition of SA, they
form 1:1 complexes with the added protein (PhS/SA) with strong and
narrow NIR absorption bands. The narrow-band absorption is
proportional to the (PhS/SA) concentration enabling calculation of
the association constant Ka through the following equation:
.times. ##EQU00001## where [SA].sub.0 is the analytical
concentration of the added SA and [PhS/SA] is the concentration of
the photosensitizer complexed with SA calculated from the spectral
changes. In Vitro Studies
(iv) Cell Culture.
Mouse embryonic heart endothelial cells (H5V) monolayers were
cultured in Dulbecco's modified Eagle's medium (DMEM)/F12
containing 25 mM HEPES, pH 7.4, 10% fetal calf serum (FCS), 2 mM
glutamine, 0.06 mg/ml penicillin and 0.1 mg/ml streptomycin at
37.degree. C., in 8% CO.sub.2. Human umbilical vein endothelial
cells (HUVEC) were maintained in M199 medium (with glutamine and
EARLE's salts) containing 10 mM HEPES, pH 7.4, 20% heat inactivated
FCS (56.degree. C., 30 min), 2 mM glutamine, 50 mg/ml gentamycin,
25 .mu.g/ml endothelial cell growth factor (ECGF), 5 IU/ml heparin
at 37.degree. C., in 5% CO.sub.2. H5V cells were kindly provided by
Dr. Annunciata Vecci, Instituto Mario Negri, Milan, Italy. HUVEC
cells were obtained from Rambam Medical Center, Haifa, Israel.
(v) Solubilization of Sensitizers, Peptides and their Conjugates
for In Vitro Cell Culture Experiments.
Water-soluble compound 8 and conjugate 11 were dissolved in culture
medium (DMEM/F12) or 10% FCS in medium or 10 .mu.M BSA in medium or
PBS prior to use, as described for each experiment. Water insoluble
compounds (RGD-4C, cycloRGDfK, compound 10 and conjugate 23) were
dissolved in 100% DMSO before use and diluted in culture medium or
PBS to a final DMSO concentration of 2% v/v. Compound 24 was
dissolved in 100% DMSO before use and diluted in saline to a final
DMSO concentration of 5% v/v.
(vi) Light Source.
The light source for in vitro studies was home-built 100-W halogen
lamp equipped with a high-pass filter (>650 nm, Safelight filter
1A Eastman Kodak Co., Rochester, N.Y., USA) and a 4-cm water
filter. The lamp was used to illuminate (20 mW/cm.sup.2/10 min (12
J/cm.sup.2)) the culture plates from the bottom at room temperature
in a dark room.
(vii) Phototoxicity Assay of the RGD Peptide-Photosensitizer
Conjugates.
To determine the pigment photodynamic efficacy in vitro under
standard conditions, cells were cultured in 96-well plates and
preincubated for 15 or 90 min at 37.degree. C. or 4.degree. C.,
according to the indicated experiment protocol, with 0-25 .mu.M
conjugated or non-conjugated photosensitizer in different media
conditions (culture medium DMEM/F12; 10% FCS in medium or 10 .mu.M
BSA in medium) in the absence or presence of excess free peptide
(100 fold up to 1 mM). The cells were washed and illuminated (20
mW/cm.sup.2 for 10 min). Plates were placed back in the culture
incubator for 24 h. Cell survival was determined using Neutral Red
cell viability assay. Cell survival was calculated as the percent
of the dye accumulated in the untreated controls. Triplicate
determinations were conducted and representative experiments are
shown. Three kinds of controls were used: (i) light control: cells
illuminated in the absence of pigments; (ii) dark control: cells
treated with pigments but kept in the dark; and (iii) untreated
cells that were kept in the dark.
(viii) Neutral Red Cell Viability Assay.
Following photosensitization and a 24-h incubation period
(37.degree. C.), cell survival was determined by Neutral Red (Fluka
Chemie, Buchs, Switzerland) accumulation. After subtraction of
assay blanks, net optical density (570 nm) was computed as the
average value of triplicates determinations. Cell survival was
calculated as the percent of the dye accumulated in the untreated
controls.
(ix) Cell Detachment (Rounding) Assay:
H5V cells were cultured as monolayers in 3-cm dish for 24-48 h, and
further incubated for 1 h with 100 .mu.M RGD-4C at 4.degree. C. or
37.degree. C. The cells were washed once and re-incubated for three
hours with fresh culture medium at 37.degree. C. In the same
fashion, HUVEC were cultured as monolayers in 6-well plate
pre-coated with gelatin for 48 h, and incubated for 1 h with 100
.mu.M RGD-4C at 37.degree. C. The cells were washed once and
re-incubated for 24 h with fresh culture medium at 37.degree. C.
The morphological changes of the cells were documented using light
microscopy.
In Vivo Studies
(x) Animals:
Male CD1 nude mice (7-8-week old, --30 g) were housed and handled
with free access to food and water in the animal facility according
to the guidelines (1996) of the Institutional Animal Care and Use
Committee of the Weizmann Institute of Science, Rehovot,
Israel.
(xi) Xenograft, Graft and Metastases Tumor Models.
Cultured rat C6 glioma cell monolayers were scraped under saline
with a rubber policeman. Single-cell suspensions of rat C6 glioma
(2-4.times.10.sup.6 cells/mouse, 50 .mu.l) were implanted
subcutaneously (s.c.) on the backs of the mice. The glial cell
strain, C6, was cloned from a rat glial tumor induced by
N-nitrosomethylurea after a series of alternate culture and animal
passages. Tumors reached treatment size, i.e. diameter of 7-9 mm,
within 2-3 weeks. Rat C6 glioma cells were kindly provided by Prof
Michal Neeman, Weizmann Institute of Science, Rehovot, Israel.
Cultured BALB/c CT26luc colon carcinoma cell monolayers transfected
with luciferase were scraped under saline with a rubber policeman.
Single-cell suspensions of CT26luc (2-4.times.10.sup.6 cells/mouse,
50 .mu.l) were implanted subcutaneously (s.c.) on the backs of the
mice. CT26 is an N-nitroso-N-methylurethane-(NNMU) induced,
undifferentiated colon carcinoma cell line. It was cloned to
generate the cell line designated CT26WT, which was stably
transduced with luciferase to obtain the lethal subclone CT26luc.
Tumors reached treatment size, i.e. diameter of 7-9 mm, within
1.5-2 weeks. CT26luc cells were kindly provided by Dina Preise,
Weizmann Institute, Rehovot, Israel.
Cultured BALB/cfC3H 4T1luc mammary gland tumor cell monolayers
transfected with luciferase were scraped under saline with a rubber
policeman. Single-cell suspensions of 4T1luc (2-4.times.10.sup.6
cells/mouse, 50 .mu.l) were implanted subcutaneously (s.c.) on the
backs of the mice. 4T1 is a 6-thioguanine resistant cell line
selected from the 410.4 tumor without mutagen treatment, which was
stably transduced with luciferase to obtain the lethal subclone
4T1luc (kindly provided by Shimrit Ben-Zaken, Weizmann Institute,
Rehovot, Israel). Tumors reached treatment size, i.e. diameter of
7-9 mm, within 1 week.
Mammary fat pads (left, bottom nipple) of female mice were
inoculated with harvested MDA-MB-231-RFP human breast cancer cells
(4.times.10.sup.6 in 100 ml saline). Tumors were classified as
`small` (.about.100 mm.sup.3) at one to two weeks from time of cell
injection, or `large` after three to four weeks (necrotic tumors,
250 to 500 mm.sup.3). To avoid tumor burden, mice were sacrificed
(cervical dislocation) when tumor size reached 10% of body weight
or at 90 days post-implantation. External caliper measurements,
length (L), width (W) and depth (D) were used to calculate in vivo
tumor volume according to the formula: V=L/2W/2D/2.pi.4/3.
Cultured metastatic human breast cancer MDA-MB-231 cell (ATCC, USA)
monolayers were scraped under saline with a rubber policeman.
Single-cell suspensions of rat human breast cancer
(2-4.times.10.sup.6 cells/mouse, 50 .mu.l) were implanted s.c. on
the backs of the mice. Tumors reached treatment size, i.e. diameter
of 7-9 mm, within 1 week.
Cultured human OVCAR-8 ovarian adenocarcinoma cell monolayers
(kindly provided by Prof Mordechai Liscovitz, Weizmann Institute,
Rehovot, Israel) were scraped under saline with a rubber policeman.
Single-cell suspensions of human OVCAR-8 ovarian adenocarcinoma
(2-4.times.10.sup.6 cells/mouse, 50 .mu.l) were implanted s.c. on
the backs of the mice. OVCAR-8 are derived from a
chemotherapy-treated patient with a metastatic disease. Tumors
reached treatment size, i.e. diameter of 7-9 mm, within 3-4
weeks.
Cultured MLS human carcinoma cell monolayers (kindly provided by
Prof Michal Neeman, Weizmann Institute, Rehovot, Israel) were
scraped under saline with a rubber policeman. Single-cell
suspensions of human MLS cells (2-4.times.10.sup.6 cells/mouse, 50
.mu.l) were implanted s.c. on the backs of the mice. Tumors reached
treatment size, i.e. diameter of 7-9 mm, within one week.
Groin Metastases.
Cultured CT26luc cells (1.times.10.sup.6 cells/mouse, 20 .mu.l)
collected in saline were s.c. injected in the distal dorsal foot of
the hindleg of anesthetized mice. When the needle was injected
below the skin, the handle of the syringe was withdrawn to verify
that it had not penetrated a blood vessel. In this way, systemic
dissemination of tumor cells was avoided. Primary tumors grew to a
size of 6-8 mm within 3 weeks. Metastases in the groin were
inspected using Xenogen IVIS.RTM. Imaging System as described
herein and by palpation.
Lung Metastases Model.
Cultured CT26luc or 4T1luc cells (0.8-1.times.10.sup.6 cells/mouse,
300 .mu.l) collected in saline were i.v.-injected in the tail vain
of anesthetized mice. Lung metastases in the lungs were inspected
using Xenogen IVIS.RTM. Imaging System as described herein, 2-3
weeks after cells injection.
The mice were sacrificed (according to the guidelines of the
Weizmann Institute of Science) when tumors reached the diameter of
>15 mm.
(xii) Anesthesia:
Mice were anesthetized by an intraperitoneal (i.p.) injection of a
mixture of 50 .mu.l ketamine (100 mg/ml; Rhone Merieux, Lyon,
France) and xylazine (2%; Vitamed, Benyamina, Israel) (85:15,
vol:vol).
(xiii) Light Source:
The light source for in vivo studies is a 763 nm or 755 nm diode
laser (1W; Ceramoptec, Bonn, Germany) according to the
photosensitizer in use.
(xiv) Solubilization of Sensitizers and their Conjugates for Animal
Experiments.
The water-soluble conjugates were dissolved in PBS or in 5% aqueous
mannitol prior to use. The pH was adjusted to a pH of 7.2 to 7.4
with Tris HCl (10 mM tris(hydroxymethyl) aminomethane (when
dissolved in 5% aqueous mannitol). The water-insoluble conjugates
were dissolved in 100% DMSO before use and diluted in saline or PBS
to a final DMSO concentration of 5% v/v. The obtained solutions
were filtered through 0.2 .mu.m polytetrafluoroethylene (PTFE)
filters (National Scientific, Rockwood Tenn., USA). Concentrations
were spectrophotometrically determined in methanol at 747 nm, using
molar extinction coefficients of 1.2.times.10.sup.5
M.sup.-1cm.sup.-1 for Pd-containing and 6.3.times.10.sup.4
M.sup.-1cm.sup.-1 for Pd free compounds. The solutions were stored
in the dark at -20.degree. C. until use.
(xv) Biodistribution Studies.
Anesthetized mice were i.v. injected (tail vein) with the different
photosensitizer (pigment) conjugates (control group: untreated).
The mice were sacrificed at indicated time points and samples of
the indicated organs and tissues (blood, tumor, intestine, liver,
spleen, kidneys, testies, heart, lung, brain, skin, muscle and fat)
were placed in pre-weighted vials and immediately frozen and stored
at -20.degree. in the dark until analyzed. Three methods were used
for sample preparation: (1) Each sample was thawed and homogenized
in DDW (1:10 w/v). Aliquots of the homogenate (500 .mu.l) were
lyophilized in Eppendorf test tubes. Then, 60 .mu.l of HNO.sub.3
(70%, TraceSelect, Fluka) were added to each dry sample, incubated
for 1 h at 90.degree. C. and diluted with DDW to 3 ml. (2) Each
sample was diluted (1:2 w/v) in HNO.sub.3 (70%, TraceSelect,
Fluka). The samples were sonicated for 30 min in boiled water, and
left for at least 48 h at room temperature. (3) Applied for
assessment of non-metalated conjugates. Each sample was thawed and
homogenized in methanol (100 mg tissue/ml) and extracted the next
morning by centrifugation (13,000.times.g, five minutes) at room
temperature. In methods (1) and (2), 140 .mu.l from each sample was
added to 3.36 ml DDW to give total volume of 3.5 ml and incubated
for 1 h at 90.degree. C. Pd concentrations were determined by
ICP-MS. According to method (3), the supernatants were diluted in
methanol by a factor of two and the drug concentration was
determined by fluorescence measurements (Varian-Cary Eclipse
spectrofluorimeter, Palo Alto, Calif., USA) at 750 nm (peak
values). Drug concentrations were interpolated from a fluorescence
calibration curve, based on predetermined drug concentrations using
absorption spectroscopy.
(xvi) Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) was
performed for determination of Pd concentrations using an ELAN-6000
instrument (Perkin Elmer, CT).
(xvii) In Vivo Whole Body Fluorescence Imaging.
The in Vivo Optical Imaging System (IVISR100/XFO-12, Xenogen Corp.,
Alameda, Calif., USA) was used to acquire fluorescent images of the
RFP-expressing tumors, as well as photosensitizers associated with
tissues and organs after their intravenous (i.v.) infusion to the
tested animals. The field-of-view was 15 cm. Two images were taken;
the first image is black and white, providing a photograph of the
animal. The second image is a colored overlay of the emitted photon
data, in the present case the NIR fluorescence of the compound
(680-720 nm excitation filter and a 780-810 nm emission filter) or
bioluminescence (560 nm) as described below. The CCD integration
time was 10-20 sec in order to maintain a high signal-to-noise
ratio.
RFP fluorescence, in units of photons/sec, was detected using
525/50 nm and 612/75 nm filter sets for excitation and emission,
respectively, with one second integration time. NIR fluorescence of
the different photosensitizers, in units of photons/sec, was
detected using 680/30 nm and 847/75 nm filter sets for excitation
and emission, respectively, at an integration time of five seconds.
Background fluorescence for all quantitative analyses was
calculated by recording the average fluorescence
(photons/sec)/cm.sup.2 from three animals in three different areas
around and within the tumor of untreated animals provided with a
similar diet for three days before measurements. Drug accumulation
was determined following i.v. administration of molar equivalents
of the photosensitizer to the tail vein of mice fed with a
chlorophyll-free, purified diet for three days before
administration (in order to reduce skin and food autofluorescence).
Before imaging, mice were anesthetized by intraperitoneum injection
of a 30 .mu.l mixture of 85:15 ketamine:xylazine.
Dynamic fluorescence images were acquired immediately following the
injection of a conjugate of the invention and continued for
approximately 2 hours. Fluorescence images were also obtained under
isoflurane anesthesia for up to 72 hr after initial injection of
the conjugate. The injected dose varied from 140 to 250 nmol per
animal. Xenogen Living Image Software (Xenogen Corp., Alameda,
Calif., USA) was used for sequential fluorescent image acquisition
and superimposition of photographic images of mice and color-coded
fluorescent images. Statistical analysis was performed using
Origin8.1 (OriginLab, Northampton, Mass., USA) and SPSS15 (SPSS
Inc, Chicago, Ill., USA) softwares.
(xviii) Luciferin Assay.
Localization and viability of CT26luc and 4T1luc tumor cells
transplanted in mice were accurately assessed by in vivo
bioluminescence imaging (BLI). According to the present invention,
BLI relies on the light-emitting properties of the reporter enzyme
firefly luciferase, which catalyses the transformation of its
substrate D-luciferin into oxyluciferin leading to the emission of
photons. Luciferin is a chemical substance found in the cells of
various bioluminescent organisms. When luciferin is oxidized under
the catalytic effects of luciferase and ATP, a bluish-green light
is produced. Firefly luciferin is a particularly good reporter for
in vivo biophotonic imaging due to properties of its emission
spectra. The emission peak of firefly luciferase (560 nm) is
contained within the spectrum of visible light and can be detected
and quantified with low light imaging systems such as the IVIS
system. Prior to imaging, mice were injected intraperitoneally with
D-luciferin (for whole body imaging: 55 mg/kg of body weight; for
lungs and lymph node metastases imaging: 77 mg/kg of body weight).
In vivo images were acquired with the Xenogen IVIS.RTM. Imaging
System 100 Series and analyzed with the Living Image.RTM. 2.5
software. Luciferin can be used in a number of ways. It can be used
to monitor light production in vivo, and can be monitored with a
Xenogen IVIS.RTM. Imaging System.
(xix) PDT Protocol.
CD-1 nude male mice bearing the different tumor xenografts were
anesthetized and 24 (5-24 mg/kg body weight) or 8 (9 mg/kg body
weight) were i.v. injected via the tail vein. The tumors were
trans-cutaneously illuminated after 3.5, 6, 8, 12 and 24 hours for
5-30 min at light doses of 30-360 J/cm.sup.2. Intensity of
illumination: 100-200 mW/cm.sup.2. After treatment, the mice were
returned to the cage. The mice were considered cured if tumor free
for 90 days after treatment. Mice were euthanized when the tumor
diameter reached 15 mm. The controls used were: (1) dark control,
the mice were i.v.-injected with pigment and not illuminated; (2)
light control, mice were illuminated without pigment injection; (3)
untreated control; (4) compound 8 alone: the mice were i.v.
injected with 8 and illuminated after indicated time point. (5)
Mixture of 8 and cycloRGDfK: the mice were i.v. injected with
mixture of 8 with cycloRGDfK and illuminated after indicated time
point. (6) cycloRGDfK alone: the mice were i.v. injected with
cycloRGDfK and illuminated after indicated time point. Images were
taken at indicated time post PDT.
(xx) MRI Measurements.
Conventional spin-echo images are acquired before contrast agent
administration, in order to localize the tumor. IR snap images were
obtained before and 2, 5, 10, 20 and 30 min after injection of 9.
The parameters used for IR snap imaging were: TR/TE=9.2/2.7 ms,
field of view (FOV)=5 cm, number of experiments (NEX)=1, image
matrix=128.times.128, slice thickness 2 mm, and a 10.degree. flip
angle. A series of seven images, using inversion times of 0.05 s,
0.25 s, 0.4 s, 1.8 s, 2.5 s, 3.6 s, and 5 s were used for T1
evaluation.
Example 26. Evaluation of Binding Parameters and Biological
Activities of the Cyclic Peptide RGD-4C
The binding parameters and biological activities of the cyclic
nonapeptide RGD-4C were characterized in order to test its
suitability for vascular photosensitizer targeting.
Characterization of RGD-4C Binding Activity
(i) Preparation of Eu-Labeled RGD-4C.
The binding parameters characteristics for the
.alpha..sub.v.beta..sub.3 integrin receptor expressed on
endothelial cells (affinity, specificity and number of
receptors/cell) were determined using time resolved emission
spectroscopy with Eu-labeled RGD-4C. To this end, RGD-4C was
labeled with Eu by direct conjugation of
isothiocyanatophenyl-DTPA-Eu as described in Material and Methods.
The separation of Eu-RGD-4C from free isothiocyanatophenyl-DTPA-Eu
was carried out using Sep-Pak C-18. The column was washed with 50%
aqueous ethanol, fractions were collected and their fluorescence
measured as described in Materials and Methods. An additional wash
with 100% ethanol did not reveal the retention of any significant
amount of Eu-containing material in the column. The final product,
Eu-RGD-4C, was quantitatively eluted as a single peak (FIG. 3A), as
confirmed by mass-spectra analysis (1499 m/z) (FIG. 3B).
(ii) .alpha..sub.v.beta..sub.3 Integrin Receptor Binding Assay.
The binding activity of Eu-RGD-4C to the integrin receptor was
determined using mouse H5V endothelial cells in culture. For the
binding assay, H5V cells were plated in 48-well plate
(10.sup.5/well) for 48 h. The plates were incubated at 4.degree. C.
(in order to inhibit receptor endocytosis), washed once with ice
cold binding buffer (0.1% BSA in DMEM:F-12) and incubated for 2 h
with increasing concentrations of Eu-RGD-4C in the absence (total
binding) or presence of 1 .mu.M RGD-4C (non specific binding). The
incubation was terminated by triple washing with ice cold binding
buffer, and enhancement solution was added (300 .mu.l/well) in
order to lyse the cells and release the chelated Eu. Samples (200
.mu.l) were taken from each well and fluorescence was determined
using time-resolved fluorometry. Net specific binding was
calculated by subtraction of non-specific from total values for
each concentration. The percentages of non-specific binding from
total added ligand were 4.9%.+-.2.4% (mean.+-.SD). The ratio of
total binding to non-specific binding increased from .about.1 at
low ligand concentrations to .about.4 at the highest concentration.
The binding results and the Scatchard analysis are presented in
FIG. 4 and FIG. 5, respectively, for a representative
experiment.
The values for the binding parameters of the ligand were calculated
from the Scatchard analysis: (1/K.sub.d=K.sub.a, the tested
compound's affinity) and B.sub.max (the maximal number of binding
sites) were 37.2-41.3 nM, and 4.3-7.7 nM (1-1.8 million receptors
per cell), respectively. Thus, Eu-RGD-4C binds specifically to H5V
endothelial cells. These results confirm reports by others that
RGD-4C is a potent ligand for .alpha..sub.v.beta..sub.3integrin
receptor (affinity constant of .about.100 nM). Specific binding to
.alpha..sub.v.beta..sub.3 integrin receptor was further
demonstrated using isolated .alpha..sub.v.beta..sub.3 binding assay
as follows.
(iii) Solid-Phase Receptor Assay.
The binding of Eu-RGD-4C to isolated .alpha..sub.v.beta..sub.3
integrin receptor was determined using time-resolved fluorometry.
Each well of a microtiter plate (Nunc MaxiSorb) was coated with 50
.mu.l of purified receptor (1 .mu.g/ml in PBS) by shaking at
4.degree. C. overnight. The receptor solution was then removed, and
each well was blocked with 200 .mu.l of milk (1% w/v milk powder in
PBS, 1 hr, room temperature). The plate was then washed with 200
.mu.l of PBS once, and incubated for 1 h at 37.degree. C. with
increasing concentrations of RGD-4C in the presence of constant
amount of Eu-RGD-4C (10 million F.U./well). The ligand/competitor
solution was removed and each well was washed three times with 200
.mu.l PBS. Enhancement solution was added (200 .mu.l/well) to
release the chelated Eu. Samples (100 .mu.l) were taken from each
well and fluorescence was determined using time-resolved
fluorometry (FIG. 6). Under these experimental conditions, 100
.mu.M of RGD-4C reduced by 50% Eu-RGD-4C binding to the isolated
receptor. This value represents the highest attenuation of the
Eu-RGD-4C binding, even at RGD-4C highest concentrations.
Characterization of RGD-4C Biological Activity
The biological effect of RGD-4C binding was characterized in H5V
cells and Human Umbilical Vein Endothelial Cells (HUVEC) using the
cell-rounding assay described in Materials and Methods. The
morphological changes of the cells were documented using light
microscopy. As seen in FIG. 7B, RGD-4C at a concentration of 100
.mu.M induced 99% H5V endothelial cell detachment from the dish
(n=200), whereas only 5% rounded cells were observed in the absence
of RGD-4C (see FIG. 7A). This effect was reversible as the cells
recovered following 3 h re-incubation with fresh culture medium (8%
rounded cells in dishes with previous presence of RGD-4C versus 6%
in the absence of RGD-4C).
Similarly to H5V cells, 100 .mu.M RGD-4C induced HUVEC detachment
from the dish in a reversible manner, since the cells recovered
following 24 h re-incubation with fresh culture medium (FIG. 8:
upper panels show HUVEC cell detachment in the presence of
increasing concentrations of RGD-4C (0-200 .mu.M) while the lower
panels show recovery of the cells 24 h after replacement of the
medium with a fresh one).
Thus, the effect of RGD-4C is a reversible one since removal of
RGD-4C by extensive washing and subsequent maintenance of the
tested endothelial cells in culture for 3 h (H5V) or 24 h (HUVEC),
results in complete recovery of their adhesive capacities.
Example 27. Binding, Cellular Uptake and Localization In Vitro of
Conjugate 24
The binding pattern of the RGD-BChl conjugates is of great
importance in understanding their mode of action. Conjugate 24
presents a detectable NIR fluorescence and its cellular binding and
localization was determined in vitro using fluorescence microscopy.
Cultured H5V endothelial cells were incubated with 25 .mu.M 24 in
DMEM/F12 medium with 10% FCS for 2 hours at 37.degree. C. The cell
culture was then washed, and PBS++ was added. Using custom made
fluorescence microscope, 24 was excited at 520 nm and the emitted
fluorescence was detected at 780 nm.
As shown in FIG. 9, conjugate 24 penetrated into endothelial cells
and concentrated around the nucleus in granule-like structures.
For comparison purposes, the cellular uptake of non-conjugated
compound 8 was measured. Cultured H5V cells were incubated with 25
.mu.M 24 or 8 in DMEM/F12 medium with 10% FCS or 75% FCS for 20
minutes or 2 hours at 37.degree. C. The cell culture was then
washed, and PBS++ was added. Excitation was carried out at 520 nm
and emitted fluorescence detection at 780 nm. FIG. 10 demonstrates
that the conjugate cellular uptake was faster than that of compound
8.
Notably, high serum concentrations (75% vs. 10% FCS) attenuate the
cellular uptake of conjugate 24. Quantitative structure function
relationship studies done in our group emphasized the role of
photosensitizer structure in the interactions with serum proteins.
These studies suggest that there is an active involvement of serum
albumin in the trafficking of compound 8 both into and out of the
treated cells. Further, the cellular uptake of 8, clearance and
phototoxicity are mediated by BSA molecules that undergo continuous
receptor mediated up-take and secretion. Regarding conjugate 24,
the affinity of the bacteriochlorophyll moiety to serum albumin
modifies the conjugate bioavailability to the integrin receptor
.alpha..sub.v.beta..sub.3. This can explain the observed decrease
in cellular accumulation in the presence of high serum protein
concentrations (FIG. 10). The higher in vitro accumulation of
conjugate 24 compared to compound 8 at each time point that was
tested could be explained by the fact that the RGD conjugate can
enter the cell by integrin receptor mediated endocytosis or/and by
non specific endocytosis like the non-conjugated 8.
Example 28. In Vivo Biodistribution of Conjugate 24 and Compound
8
The conjugates of the invention are potential drug carriers.
Therefore, their in vivo biodistribution is of great importance. In
order to quantify the conjugate levels in target tissues, Ion
Coupled Plasma-Mass Spectroscopy (ICP-MS) was used for tracing the
central M atom (e.g., Pd, Cu) in the target organ. The stable
binding of the central merttal atom enables monitoring and accurate
determination of the time dependent concentration of the compound
in the target organs. Biodistribution of conjugate 24 and of
compound 8 was determined in CD1-nude male mice with tumor
xenografts of rat C6 glioma as described in Materials and Methods,
using method (2) for sample preparation. Biodistribution of 24 was
also determined in CD1-nude male mice bearing tumor grafts of mouse
CT26luc colon carcinoma and CD1-nude male mice bearing tumor grafts
of mouse of 4T1luc mammary cancer.
The results, as shown in FIGS. 11A-11C, indicate accumulation of
conjugate 24 in the different tumor tissues up to 8 hours post
injection accompanied by continuous decrease of the conjugate
levels in the blood. Moreover, the biodistribution pattern of 24
appears independent of the tumor's origin (rat C6 glioma (FIG.
11A), mouse CT26luc colon carcinoma (FIG. 11B), and mouse 4T1
carcinoma of the breast (FIG. 11C).
The biodistribution of compound 8 injected to CD1 nude mice with
tumor xenografts of rat C6 glioma presented a completely different
picture as shown in FIG. 12: compound 8 cleared rapidly from the
subject and at no time showed selective accumulation or retention
in the tumor tissue. The accumulation of conjugate 24 in the tumor
tissue, with maximal values at 8 h post injection, as opposed to
compound 8 (FIG. 12), indicates that the potential drug carrier 24
can be used for drug targeting purposes and can be applied for
imaging of tumors and angiogenesis.
Moreover, it is to be noted that the concentrations of accumulated
conjugate within the tumor tissue reached the M level, whereas
labeled cycloRGDfK and cycloRGDfK conjugated to other metal
chelators were reported by others to reach concentrations only in
the nM range (Haubner et al., 2001; Janssen et al., 2002a; Janssen
et al., 2002b; Temming, 2005). These reported results demonstrate
rapid tumor up-take of the conjugated peptides with maximal peak
concentration at 30 min, 1 hour or 2 hours post injection,
depending on the conjugate structure. Thus, the markedly increased
tumor uptake of the conjugates of the invention compared to either
M-Bchl derivative alone or GRD-containing peptide conjugated to
other chelators, can be attributed to the conjugation of the
RGD-containing peptide to the BChl moiety.
The relative levels of 24 in the tumor tissue and blood are
illustrated in FIG. 11C, and it is shown that while 8 hours post
injection the conjugate reached maximum concentration in the tumor,
at 24 hours post injection its concentration in the tumor relative
to the blood and surrounding normal tissue, is still sufficiently
high to enable a selective vascular-targeted imaging (VTI) and
possibly vascular-targeted PDT (VTP).
It is to be noted that the concentration of the conjugate in the
tumor tissue relative to other organs was significantly lower in
tumors where the cells are known not to express
.beta..sub.v.beta..sub.3 integrin (e.g. CT26luc). Thus, the
observed accumulation in .alpha..sub.v.beta..sub.3 negative tumors
is probably due to their vascular up-take.
Example 29. In Vivo Biodistribution of Conjugate 15
The biodistribution of Cu-conjugate 15 was determined in female
CD-1 nude mice of 6-8 weeks-old, weighing 20-23 g and bearing
6-9-mm.sup.3 tumors of human adenocarcinoma cells obtained from
breast tissue (MDA-MB-231 cells). The conjugate (30 mg/ml in 5%
DMSO/PBS) was injected to the tail vein, and the animals were
sacrificed in selected time points. Cu concentrations were
determined by ICP-MS as described in Material and Methods. The
ICP-MS results after the subtraction of time 0 are shown in FIG.
13.
The obtained data showed an obvious accumulation of 15 in tumor
with a peak at 8-12 h after injection of about 3-fold intensity in
comparison with surrounding normal tissue.
Example 30. In Vivo Biodistribution of Conjugate 42
In order to assess the actual role of RGD/integrin recognition, the
biodistribution of the conjugate 42, in which glycine in the
peptide is replaced with alanine, was measured and compared to the
biodistribution of conjugate 24. The substitution of only one amino
acid was demonstrated by others to interfere with the integrin
recognition (Pierschbacher and Ruoslahti, 1987). Mostly, RAD or RGE
peptides were used for this purpose. The biodistribution assay was
performed as described in Example 26 above using CD1 nude male mice
with tumor grafts of mouse CT26luc colon cancer cells, and Pd
concentrations were determined by ICP-MS. The ICP-MS results are
shown in FIG. 14A.
Comparison between the biodistribution of conjugate 24 and the
conjugate 42 (FIG. 14B) demonstrates that RGD conjugate uptake in
tumor tissue was faster than that of RAD conjugate and to a higher
extent up to 24 hours. Conjugate 24 accumulated in the tumor tissue
with maximal peak concentration at 8 hours post injection
accompanied by a continuous decrease of the conjugate levels in the
blood, while the concentrations of 42 in the tumor tissue and blood
8 hours post injection are quite the same. Importantly, both
conjugates presented a prolonged basal level after administration
due to non-specific binding. However, the accumulation of the RGD
conjugate in the tumor site was twice as much compare to the RAD
conjugate.
Example 31. In Vivo Fluorescence Imaging of Mice Bearing Rat C6
Glioma Xenografts Following Treatment with Conjugate 24 or Compound
8
Dynamic fluorescence images were obtained from CD-1 nude male mice
bearing rat C6 glioma xenografts. The fluorescence images were
acquired using IVIS system as described in Materials and Methods.
Clearance of the injected photosensitizers (compound 8 or conjugate
24) was measured in mice by fluorescence imaging and is
demonstrated in FIG. 15. Mice bearing rat C6 glioma xenografts on
the back of the right posterior limb were injected with 200 nmol
dose of conjugate 8 (mice in upper pictures) or 200-nmol dose of 24
(mice in lower pictures), and images were taken at 4, 24, 48 and 72
hours post-injection.
Except for a residual fluorescence from the liver and spleen, no
specific signal could be seen from the animal treated with the
compound 8 at times longer than 4 hours post injection in agreement
with the ICP-MS data (FIG. 12). Conjugate 24 appears to accumulate
in the tumor, spleen, liver and a fat hump below the animal head.
These imaging results, when combined with the ICP-MS results,
suggest that the best time window for imaging and probably
treatment of the tumor by VTP is at 8-24 hours after drug
administration.
Example 32. Dynamic Fluorescence Imaging of Mice Bearing Mouse
CT26luc Colon Cancer Grafts Transfected with Luciferase Following
Treatment with Conjugate 24
Cell lines transfected with luciferase generate visible light in
the presence of luciferin when alive. The luciferin luminescence
enables to monitor viable tumor cells and thus provides the means
to validate the conjugate's homing at the tumor site, its imaging
capability and the efficacy of VTP.
To avoid the theoretical possibility of conjugate excitation by the
luciferin bioluminescence, the fluorescence images were recorded
and only then the animals were i.p. injected with luciferin and the
bioluminescence of the transfected tumor cells was detected.
The results show that there is a complete overlap between the
region of NIR fluorescence signal coming from conjugate 24 and the
region of endogenous bioluminescence signal that originates in the
tumor cells themselves.
Dynamic fluorescence images were obtained from CD-1 nude male mice
bearing grafts of mouse CT26luc colon cancer transfected with
luciferase, following the intravenous injection of an integrin
receptor targeting conjugate 24. FIGS. 16B-16C depict fluorescence
and luminescence images of a mouse bearing a graft on the back of
the right posterior limb, 24 hours after injection of 200-nmol dose
of conjugate 24. The fluorescence and luminescence images were
acquired using Xenogen IVIS.RTM. Imaging System as described in
Material and Methods.
The results show that there is a complete overlap between the
region of NIR fluorescence signal coming from conjugate 24 and the
region of endogenous bioluminescence signal that originates in the
tumor cells themselves.
Example 33. Dynamic Fluorescence Imaging of Mice Bearing 4T1luc
Mammary Cancer Grafts Transfected with Luciferase Following
Treatment with Conjugate 24
Dynamic fluorescence images were obtained from BALB/c female mice
bearing grafts of mouse 4T1luc mammary cancer transfected with
luciferase, following the intravenous injection of an integrin
receptor targeting conjugate 24. FIGS. 17A-17C show photographs
fluorescence and luminescence images of two female mice bearing a
subcutaneous mouse 4T1 mammary gland cancer transfected with
luciferase grafts on the back of the right posterior limb, 24 hours
after the injection of 200-nmol dose of conjugate 24. The
fluorescence and luminescence images were acquired using IVIS
system as described in Material and Methods.
The results show that there is a complete overlap between the
region of NIR fluorescence signal coming from conjugate 24 and the
region of endogenous bioluminescence signal that originates in the
tumor cells themselves.
Example 34. Dynamic Fluorescence of Mice Bearing Ovarian Carcinoma
(MLS) Following Treatment with Conjugate 26
Conjugate 26 (8 mg/kg) was i.v. injected into animals bearing MLS
ovarian carcinoma. Images on IVIS were taken after 8 and 14 hours.
As shown in FIG. 18, the conjugate did not present accumulation
after (B) 8 hours, but at (C) 14 hours a high level of fluorescence
was observed in tumor and liver areas.
Example 35. Fluorescence Imaging Demonstration of In Vivo Binding
Specificity of Conjugate 24 to .alpha..sub.v.beta..sub.3 Integrin
Receptor
Specific binding is defined as one inhibited by the unconjugated
sensitizer. Thus, in order to demonstrate the in vivo binding
specificity of conjugate 24, attempts to block its accumulation
were carried by competing with free cycloRGDfK for binding of the
same binding sites. Fluorescence imaging was performed 24 hours
after administration of 140 nmol of conjugate 24 alone (FIG. 19,
left mouse on both panels, with tumor on the back of the right
posterior limb), or administration of 140 nmol of conjugate 24 1
hour after injection of excess "free" (8.5 .mu.mol) cycloRGDfK
peptide to mice bearing C6 glioma xenografts (FIG. 19, right mouse
on both panels, with tumor on the back of the left posterior limb).
Fluorescence images of the blocked receptor xenografts with the
same exposure time are illustrated in FIG. 19 on the same linear
color scale to allow for a qualitative comparison. The fluorescence
intensity originating from the tumor was larger when conjugate 24
was administered alone as compared to when the peptide cycloRGDfK
was administered one hour prior to imaging agent administration. In
normal tissues, the uptake was not influenced by the
pre-administration of cycloRGDfK.
The results show that the uptake of conjugate 24 in tumor regions
were: (i) significantly greater than in the contralateral normal
tissue regions; and (ii) blocked by pre-injection of cycloRGDfK in
excess. Taken together, one can conclude that "free" cycloRGDfK
inhibits the accumulation of conjugate 24, and the reduced uptake
of conjugate 24 resulting from pre-administration of cycloRGDfK in
excess validates the in vivo molecular specificity of the conjugate
to .alpha..sub.v.beta..sub.3receptors.
Example 36. Dynamic Fluorescence Imaging Following Treatment with
Conjugate 42
In order to asses the actual role of RGD/integrin recognition in
vivo, dynamic fluorescence images were obtained from CD-1 nude male
mice bearing CT26luc grafts on the back of the posterior limb, 24
hours after the administration of conjugate 24 (FIG. 20, left mouse
in each panel) or conjugate 42, in which glycine in the peptide is
replaced with alanine (cycloRADfK); right mouse in each panel).
Since the fluorescence signal of the RGD conjugate at the tumor
tissue reaches a maximum at 3.5-4 hours post injection, images are
presented taken 4 hours post injection. Importantly, both
conjugates present a prolonged basal level of fluorescence after
administration due to non-specific binding. However, the
fluorescence intensity of the RGD conjugate is clearly higher than
that of the RAD conjugate in the tumor site. These results are
supported quantitively by ICP-MS measurements showing almost twice
as much accumulation of the RGD conjugate in the tumor tissue (see
Example 30 above and FIG. 14A).
Since the CT26luc cells lack .alpha..sub.v.beta..sub.3 (although
they likely express some .alpha..sub.v.beta..sub.5) (Yao et al.,
2005; Borza et al., 2006), the higher fluorescence of 24 from the
tumors probably originates in their ligation (via the RGD
tripeptide) to the neoendothelial .alpha..sub.v.beta..sub.3
integrins.
FIG. 21 depicts the fluorescence images of CD1 nude mice bearing
tumors that originate in human ovary adenocarcinoma OVCAR-8, mouse
colon cancer CT26luc, human epithelial ovarian carcinoma MLS, and
mouse mammary carcinoma 4T1luc cell lines, 24 h after
administration of conjugate 24. Integrin .alpha..sub.v.beta..sub.3
is expressed on some types of solid tumor cells. Regarding the cell
lines above, MLS (Schiffenbauer et al., 2002), and 4T1luc (Mi et
al., 2006), overexpress integrin .alpha..sub.v.beta..sub.3
receptors on their cell surface, while mouse CT26luc lack integrin
.alpha..sub.v.beta..sub.3 receptors, but express some
.alpha..sub.v.beta..sub.5 (Yao et al., 2005; Borza et al., 2006),
and OVCAR-8 lack .alpha..sub.v integrins (Ross et al., 2000).
Indeed, the fluorescence signal was significantly higher for
integrin .alpha..sub.v.beta..sub.3 positive cells (MLS and 4T1luc)
compared to integrin .alpha..sub.v.beta..sub.3 negative cells
(CT26luc and OVCAR-8), probably due to additional accumulation in
the tumor cells themselves. The observed difference between the
compound accumulation in the two .alpha..sub.v.beta..sub.3 negative
tumors (CT26luc and OVCAR-8) probably reflects (i) a difference in
their neovascularization since they both lack the
.alpha..sub.v.beta..sub.3 integrins, (ii) might be due to
additional accumulation in the CT26luc tumor cells themselves,
since they express .alpha..sub.v.beta..sub.5 that can binds
specifically the RGD-BChl conjugate.
Example 37. Dynamic Fluorescence Imaging of Lung Metastases
Detection of a 4T1luc model of breast cancer metastases in the
lungs was enabled by conjugate 24, 24 h post injection into BALB/c
female mouse (15 mg/kg) (FIG. 22). These results show that the
uptake of 24 in metastatic regions in the lungs can be monitored by
fluorescence at relatively high accuracy.
Next, CT26luc model metastases in the lungs were detected as a
function of time post 24 injection (4, 9 and 24 h, 15 mg/kg; FIGS.
23A-23I). CD-1 nude male mice bearing CT26luc lung metastases that
were not injected with the conjugate served as controls (FIGS.
23G-23H) and a CD-1 nude male mouse without lung metastases that
was i.v. injected with conjugate 24 (FIG. 23I). The fluorescence
imaging results show that the uptake of 24 in metastatic regions
was significantly higher than by the surrounding normal tissue
regions, with best tumor to background ratio at 24 hours after
administration.
Example 38. Dynamic Fluorescence Imaging of Lymph Node
Metastases
CD-1 nude male mouse bearing CT26luc primary tumor on the back of
its left leg and metastases in the near lymph node, was imaged and
photographed 24 hours after the i.v. injection of conjugate 24 (15
mg/kg). Detection of the CT26luc metastases in the lymph node was
abled by localization of conjugate 24. The black & white
photograph, bioluminescence signal originated from the reaction of
luciferin with the luciferase transfected tumor cells, and the
fluorescence image of the mouse are shown in FIG. 24.
These results indicate that tumors in both primary and metastatic
regions (lungs, lymph nodes) can be monitored by fluorescence at
relatively high accuracy.
Example 39. In Vivo Magnetic Resonance Imaging (MRI) of Mice
Bearing Rat C6 Glioma Xenografts Using Compound 9 as a Contrast
Agent
Measurements were performed on CD1 nude male mice (average weight
.about.30 g) bearing the C6-glioma xenografts (10-15 mm diameter;
left flank, subcutaneous). Seven mice were used for MRI enhanced
with Mn-13.sup.2-OH-Bpheid (compound 9) (15 .mu.mol/kg).
Calculated graphs of signal intensity ratio and relaxivity ratio
revealed that compound 9 at a dose of 15 .mu.mol/kg increased the
tumor/normal relaxivity ratio from 0.8-1.0 up to .about.1.4, in
about 10 min after injection of the substance. The contrast effect
obtained with 9 was higher than that known for Gd-containing
contrast agents.
Taking the higher contrast obtained by compound 9 in comparison
with Gd agents and the expected prolonged residence of the
corresponding Mn-containing cycloRGDfK conjugate 12 in the tumor,
that enables long integration of the MR signal, we anticipate
superior imaging with this conjugate over other contrast agents
such as Gd-DTPA.
Example 40. In Vitro Targeted Phototoxicity
In order to evaluate the photodynamic potency of the RGD
peptide-photosensitizer conjugate versus that of the non-conjugated
photosensitizer, the phototoxicity of conjugate 23 and the
unconjugated photosensitizer 10 were determined by monitoring the
survival of cultured H5V endothelial cells following PDT.
H5V cells were incubated for 90 min at 37.degree. C. with 0-25
.mu.M of conjugate 23 or compound 10 in different media conditions,
illuminated and their survival was determined using Neutral Red
viability assay as described in Materials and Methods. The
dose-response survival curves of the H5V cells treated with the
photosensitizers under different conditions are shown in FIGS.
25A-25C: 10% FCS in medium (FIG. 25A), culture medium DMEM/F12
(25B) and 10 .mu.M BSA in medium (25C).
The phototoxic effects of conjugate 23 and compound 10 in different
media were found to be light- and drug concentration-dependent.
Based on the LD.sub.50 values we can conclude that the photodynamic
potency of the conjugate 23 is higher than that of the
non-conjugated photosensitizer 10.
Targeted phototoxicity is defined as one inhibited by the free
ligand. Thus, further experiments attempted to block phototoxicity
by administration of the free cycloRGDfK, which competes for the
cellular binding of conjugate 23. H5V cells were incubated for 90
min at 37.degree. C. with 0-25 .mu.M of compound 10 or conjugate 23
in different media (10% FCS in medium or 10 .mu.M BSA in medium) in
the absence or presence of free excess cycloRGDfK (100-fold up to 1
mM). The cells were illuminated and cell survival was determined
using Neutral Red viability assay, as described above.
As shown in FIGS. 26A-26D, presenting the dose-response survival
curves of treated cells, and as indicated by the LD.sub.50 values
presented in Table 2, the phototoxic effects of 23 and 10 were not
influenced by the presence of excess cycloRGDfK.
TABLE-US-00002 TABLE 2 LD.sub.50 values of conjugate 23 and
compound 10 in absence and presence of free peptide in excess in
different reaction conditions Compound Conj. 23 Comp. 10 with free
with free Reaction peptide in peptide in Conditions Conj. 23 excess
Comp. 10 excess 10 .mu.M BSA in 0.5-1 .mu.M 1 .mu.M 3.5-5 .mu.M 5
.mu.M medium (FIGS.16C, 17D) (FIG. 17D) (FIGS. 16C, 17B) (FIG. 17B)
(90 min, 37.degree. C.) culture medium 1 .mu.M Not done .sup. 7
.mu.M Not done (90 min, 37.degree. C.) (FIG. 16B) (FIG. 16B) 10%
FCS 1-4 .mu.M 4 .mu.M .sup. 5-7 .mu.M 5 .mu.M (90 min, 37.degree.
C.) (FIGS. 16A, 17C) (FIG. 17C) (FIGS. 16A, 17A) (FIG. 17A) 10% FCS
3.5 .mu.M 2.4 .mu.M Not done Not done (15 min, 37.degree. C.) (FIG.
18A) (FIG. 18A) 10% FCS 20 .mu.M 8 .mu.M Not done Not done (15 min,
4.degree. C.) (FIG. 18B) (FIG. 18B)
These results suggest that the conjugate is entering the cell via
integrin-independent fluid-phase endocytosis, thus the free
cycloRGDfK cannot compete for the cellular binding with the
conjugate. The integrin-independent cell entry can be attributed to
either parts of the conjugate, the photosensitizer moiety or the
cycloRGDfK peptide. There is one report in the literature
indicating that cycloRGDfK internalizes by an integrin-independent
fluid-phase endocytosis that does not alter the number of
functional integrin receptors on the cell surface (Hart et al.,
1994; Castel et al., 2001).
In order to test the endocytosis theory and since the endocytic
process is time- and temperature-dependent, H5V cells were
incubated at 37.degree. C. and 4.degree. C. for 15 min with 0-20
.mu.M of conjugate 23 in medium containing 10% FCS, in the presence
or absence of excess cycloRGDfK (100-fold up to 1 mM). Cells were
illuminated and their survival was determined as described above.
The dose-response survival curves of the treated H5V cells are
shown in FIGS. 27A-27B.
The LD.sub.50 values measured for 15-min incubation at 37.degree.
C. or 4.degree. C. increased relatively to the values obtained upon
incubation of the cells at 37.degree. C. for 90 min (Table 2). The
LD.sub.50 values of conjugate 23 changed to 3.5 .mu.M and to 20
.mu.M following 15-min incubation at 37.degree. C. and 4.degree.
C., respectively, compared to 1 .mu.M obtained for incubation at
37.degree. C. for 90 min. The increase in LD.sub.50 values upon
lowering the temperature supports the hypothesis of a possible role
for endocytosis in the conjugate uptake.
Unexpectedly, not only the photocytotoxic effect of conjugate 23
was un-blocked by the presence of excess cycloRGDfK, but in fact,
the photodynamic activity of 23 under 15-min incubation at
37.degree. C. or 4.degree. C. was higher in the presence of free
cycloRGDfK. There is a possibility that the excess of free peptide
causes the cells to be more sensitive to the PDT effect of the
conjugate due to enhanced detachment of the cells from the dish
and/or induced apoptotic signal transduction.
The phototoxicity of conjugate 24 was determined by monitoring the
survival of cultured H5V endothelial cells following PDT. H5V cells
were incubated for 2 hours at 37.degree. C. with 0-25 .mu.M
conjugate 24 in culture medium DMEM/F12 with 10% FCS. The cells
were illuminated and their survival was determined as described
above.
As shown in the dose-response survival curve (FIG. 28), the
phototoxic effects of conjugate 24 on H5V cells after 2 hr
incubation at 37.degree. C. were found to be light- and drug
concentration-dependent.
The phototoxicity of a third conjugate, 11, and of compound 8 was
also determined using H5V endothelial cells. Cells were incubated
for 90 min at 37.degree. C. in the presence of 0-20 .mu.M conjugate
11 or compound 8 in 10 .mu.M BSA in medium, illuminated and their
survival was determined as described above.
As shown in the dose-response survival curve (FIG. 29), the
phototoxic effects of conjugate 11 and compound 8 were found to be
light- and drug concentration-dependent. The LD.sub.50 values are
represented in Table 3.
TABLE-US-00003 TABLE 3 LD.sub.50 values of conjugate 11 and
compound 8 in absence and presence of free peptide excess Compound
Conj. 11 Comp. 8 with free with free Reaction. peptide peptide
Conditions Conj. 11 excess Comp. 8 excess 10 .mu.M BSA 7-10 .mu.M 5
.mu.M 1.8-2 .mu.M 2 .mu.M in medium (FIGS. 19, 20) (FIG. 20) (FIGS.
19, 20) (FIG. 20) (90 min, 37.degree. C.)
As for the cycloRGDfK peptide, blockage of the phototoxicity of
conjugate 11 by adding free cyclic RGD-4C to the cell culture
failed (FIGS. 30A-30B, Table 3). H5V cells were incubated for 90
min at 37.degree. C. with 0-10 .mu.M conjugate 11 or compound 8 in
10 .mu.M BSA in medium in the absence or presence of RGD-4C in
excess (1 mM). The cells were illuminated and their survival was
determined as described above.
Again, this result suggests that the photosensitizer's moiety
(compound 8) determines the cellular uptake of the conjugate 11 via
free endocytosis.
Example 41. In Vivo PDT in Rat C6 Glioma Tumor Using Conjugate
24
Based on the results above we developed a new treatment protocols
for PDT of solid tumors using conjugate 24. The protocol parameters
should include: Time of treatment (drug-light
interval)--Illumination 3 to 24 hours post-drug administration;
Dose (mg/kg)--5-24 mg/kg; Duration of illumination (min)--5-30 min;
Intensity of illumination (mW/cm.sup.2)--100-200 mW/cm.sup.2;
Delivered energy (J/cm.sup.2)--30-360 J/cm.sup.2.
The initial tumor models used comprised rat C6 glioma tumor
xenografts, since these tumor cells express
.alpha..sub.v.beta..sub.3 (Zhang et al., 2006) and
.alpha..sub.v.beta..sub.5 integrins (Milner et al., 1999) in
addition to integrin .alpha..sub.v.beta..sub.3 expressed on the
tumor neovasculature.
CD-1 nude male mice bearing C6 glioma grafts were i.v. injected
with 15 or 24 mg/kg body doses of conjugate 24 or 9 mg/kg body dose
of compound 8.
For each protocol we used at least 3 animals, but due to high
mortality rate we were left with limited number of animals. The
results are presented in Table 4.
TABLE-US-00004 TABLE 4 Therapeutic results of different VTP
protocols applying conjugate 24 to mice bearing rat C6 glioma. Time
Duration Intensity to treat- Dose of illu- of illu- Delivered ment
(mg/ mination mination energy No. of (hours) kg) (min) (mW)
(J/cm.sup.2) comments animals 3.5 15 5 100 30 Extensive 2 necrosis
6 15 10 100 60 Extensive 2 necrosis 8 15 5 100 30 Limited 2
necrosis 8 15 10 100 60 Limited 1 necrosis 8 24 10 100 60 Limited 1
necrosis 8 24 10 100 60 Extensive 1 necrosis 8 15 15 100 90
Extensive 1 necrosis
The protocols that appeared optimal and provided the best
therapeutic results appear in bold in Table 4: 15 mg/kg, 15-min
illumination (90 J/cm.sup.2) 8 hours post injection, and 24 mg/kg,
10-min illumination (60 J/cm.sup.2) 8 hours post injection.
FIGS. 31A and 31B show the therapeutic results of those protocols,
respectively. In dark control (FIG. 31C), the mice were i.v.
injected with conjugate 24 and not illuminated; In light control
(FIG. 31D), mice were illuminated without conjugate 24 injection;
and in unconjugated photosensitizer control (FIG. 31E), the mice
were i.v. injected with compound 8 and illuminated after 8
hours.
The different controls showed no PDT effect. In contrast, the
animals treated with conjugate 24 and light presented extensive
edema few hours post PDT treatment that developed to inflammation
and necrosis below the skin at 3 days post PDT. Tumor flattening
and long period of tumor regression as well as wound healing was
observed.
Example 42. In Vivo PDT in Mouse CT26 Colon Tumor Using Conjugate
24
Using the rat C6 glioma model we could not get immediate assessment
of VTP outcome, a major disadvantage in course of a screening
process. To overcome this problem we used the mouse CT26luc colon
carcinoma model consisting of luciferase transfected cells, which
enable fast evaluation of the therapeutic effect.
CD-1 nude male mice bearing CT26luc tumors were subjected to
different protocols of PDT with conjugate as shown in Table 5.
TABLE-US-00005 TABLE 5 Therapeutic results of different VTP
protocols applying conjugate 24 to mice bearing mice CT26luc colon
cancer. Duration Intensity Time to of of Delivered No. treatment
Dose illumination illumination energy of (hrs) (mg/kg) (min) (mW)
(J/cm.sup.2) Comments animals 8 9 15 100 90 Reduction in 3
luminescence signal, no necrosis 8 9 10 100 60 Reduction in 5
luminescence signal, no necrosis* 8 11 10 100 60 Reduction in 4
luminescence signal, extensive necrosis 8 12 10 100 60 Reduction in
3 luminescence signal, extensive necrosis 8 15 10 100 60 Reduction
in 4 luminescence signal, extensive necrosis 12 15 15 100 90
Reduction in 5 luminescence signal, limited necrosis* 24 15 30 200
360 Reduction in 3 luminescence signal, no necrosis* 24 15 30 100
180 Reduction in 2 luminescence signal, no necrosis 24 24 30 100
180 Reduction in 2 luminescence signal, no necrosis 24 24 30 150
270 Reduction in 2 luminescence signal, no necrosis 24 24 30 200
360 Reduction in 2 luminescence signal, limited necrosis
FIGS. 32A-32F show the therapeutic results of applying 15 mg/kg, 10
min illumination (60 J/cm.sup.2), 8 hours post injection of
conjugate 24 to mice bearing CT26luc tumors (bolded protocol in
Table 5). 32A--conjugate 24 was i.v. injected 15 mg/kg, 10 min
illumination (60 J/cm.sup.2) 8 hours post injection; 32B--overlaid
images taken after i.p. injection of luciferin to the mouse
described in 32A, using the IVIS system. The first image is black
and white, which gives the photograph of the animal. The second
image is color overlay of the emitted photon data. All images are
normalized to the same scale. 32C--Bioluminescence signal
quantification (photon/sec/cm.sup.2) of the data shown in B.
32D--control with compound 8 alone: the mice were i.v. injected
with compound 8 and illuminated after 8 hours. 32E--control with
mixture of compound 8 and cycloRGDfK: the mice were i.v. injected
with mixture of compound 8 with cycloRGDfK and illuminated after 8
hours. 32F--control with cycloRGDfK alone: the mice were i.v.
injected with cycloRGDfK and illuminated after 8 hours. Images were
taken at indicated time post PDT.
FIG. 32B shows overlaid images taken with the IVIS system after
i.p. injection of luciferin to the mouse depicted in FIG. 32A. FIG.
32C provides quantitative description of the bioluminescence shown
in FIG. 32B. The controls used were (1) compound 8 alone (FIG.
32D); (2) mixture of unconjugated compound 8 and cycloRGDfK (FIG.
32E); and (3) cycloRGDfK alone (FIG. 32F). The different controls
showed no PDT effect. In contrast, the animals treated with the
targeted conjugate developed necrosis within 4 days post PDT (FIG.
32A). Significant bioluminescence signal from residual tumor cells
appear 8 days post PDT (FIG. 32B), although no tumor was palpated
or visually detected. Wound healing and tumor flattening were
observed in all responding animals.
FIG. 33 shows the Kaplan-Mayer curve for the protocols indicated in
the Table 5 with asterisk.
Example 43. Tumor Diagnosis and PDT Treatment of Breast Tumors with
Conjugate 13
Human breast cancer MDA-MB-231 cells (ATCC) were transfected with
red fluorescent protein (RFP) as follows.
Plasmids--
the plasmid that was used for the transfection of the cells was
pDsRed-Monomer-Hyg-C1 (Clontech, Palo Alto, Calif.) that carries
the RFP gene and resistance gene for hygromycin in which the
DsRed-Monomer gene was replaced with pDsRed2 (from the pDsRed2-N1
plasmid).
Transfection Process--
For the transfection process, Lipofectamine.TM. 2000 (Invitrogen)
was used according to the manufacturer protocol: 4 .mu.g DNA were
incubated for 5 min with 250 .mu.l Opti-MEM medium (supplied by the
manufacturer Invitrogen). In a separate test tube, 10 .mu.l of
Lipofectamine were incubated for 5 min with 250 .mu.l Opti-MEM
medium. After incubation, the DNA and Lipofectamine solutions were
mixed and incubated for 20 min at room temperature and the content
was evenly scattered on one out of a 6-well plate that was 50-60%
confluent with the MDA-MB-231 cells.
Selection of Stable Clone--
24 hr after the transfection of the MDA-MB-231 cells, the plate was
checked under a fluorescence microscope (Nikon). A transient
transfection was detectable at this stage. The medium was replaced
with fresh medium containing antibiotics (hygromycin) at a
concentration of 250 .mu.g/ml. When the plates reached confluency,
the cells were detached from the culture plate following a 30-60
sec treatment with trypsin, and plated in a 96-well plate at a
concentration of 0.5 cells/well. Wells that contained one clone
only and the clone was fluorescent, were collected and plated in a
6-well plate. After reaching confluency they were further plated in
a 10 cm plate. FIGS. 34A-34B show the fluorescent MDA-MB-231 RFP
clone 3 (resistant to hygromycin) after 1 sec and 3 sec exposure,
respectively.
For the PDT experiments, MDA-MB-231 RFP cells (4.times.10.sup.6)
were implanted subcutaneously on the backs of the mice and tumors
developed to the treatment size (6-8 mm) within 2-3 weeks.
PDT Protocol:
Anaesthetized mice were i.v. injected with conjugate 13 (7.5 mg
drug/kg body weight). The tumors were illuminated for 10 min. The
drug light interval used was 8 hr post drug injection. Transdermal
illumination through the mouse skin with 755 nm diode laser at 100
mW/cm.sup.2 (CeramOptec, Germany) was used. After the treatment,
the mice were returned to the cage. In the dark control group, the
mice were i.v. injected with the sensitizer conjugate 13 and placed
in dark cage for 24 hr. In the light control group, the mice were
illuminated for 10 min with 100 mW/cm.sup.2. During the first 2
days post PDT, as needed, the mice received analgesia (2.5 mg/kg
Flunexin daily) and 3 days Oxycode in the drinking water. The end
point of animal survival is when the size of the tumor reaches 10%
of animal weight. Mice are sacrificed at this time (up to 90 days)
by cervical dislocation.
FIGS. 35A-35B show two representative examples to local response of
human MDA-MB-231-RFP to PDT. Mice with MDA-MB-231-RFP xenografts
(.about.0.5 cm3) on their backs were i.v. injected with 7.5 mg/kg
of conjugate 13 and illuminated 8 h later through the mouse skin
with 755 nm diode laser at 100 mW/cm.sup.2. 35A--Photographs taken
from day 0 (before treatment) and after treatment at 1, 4, 7, 12
and 90 days. By day 4 partial necrosis was seen, by day 7 tumor
flattening was observed, after 90 days the wound healed and the
animal was cured. 35B--In vivo whole-body red fluorescence imaging
of CD-1 nude male mice bearing MDA-MB-231-RFP orthotopic tumor. No
signal was detected 90 days after treatment.
In order to study the accumulation of the photosensitizer in
primary mammary tumors, the MDA-MB-231-RFP cells (4.times.10.sup.6)
were implanted orthotopicaly in the mammary pad of the mice. Tumors
developed to the wanted size, bigger than 1 cm.sup.3, within 3-4
weeks.
For the accumulation assessment, mice were anesthetized by i.p.
injection of 30 .mu.l mixture of 85:15 ketamine: xylazine, and
received an i.v. injection to the tail vein of 15 mg drug/kg body
weight conjugate 13. Fluorescence of both tumor cells and conjugate
13 are monitored by IVIS.RTM. 100 Imaging system (Xenogen). Tumor
imaging main filter set comprised: excitation filter 500-550 nm,
emission filter 575-650 nm; Background filter set for subtraction
the tissue auto fluorescence: excitation filter 460-490 nm,
emission filter 575-650 nm. Photosensitizer imaging main filter
set: excitation filter 665-695 nm, emission filter 810-875 nm.
Images were taken at these time points post drug injection: 15 min,
1, 2, 3, 4.5, 6, 7.5, 9, 24 hr, 2, 3, 4, 5, 6, 7 days. The results
are shown in FIGS. 36 and 37.
FIG. 36 shows accumulation of conjugate 13 in orthotopic human
breast MDA-MB-231-RFP primary tumor (tumor size.about.1 cm.sup.3).
Images were taken from 15 min to 24 hr post drug injection. Top
panel--In vivo whole-body red fluorescence imaging of CD-1 nude
female mice bearing MDA-MB-231-RFP orthotopic tumor. Bottom
panel--In vivo whole-body NIR fluorescence imaging of conjugate 13
accumulation. The drug shows no specific accumulation in the tumor
during the first 24 h.
FIG. 37 shows accumulation of conjugate 13 in orthotopic human
breast MDA-MB-231-RFP primary tumor (tumor size.about.1 cm.sup.3).
Images were taken from day 1 to 6 post drug injection. Top
panel--In vivo whole-body red fluorescence imaging of CD-1 nude
female mice bearing MDA-MB-231-RFP orthotopic tumor. Bottom
panel--In vivo whole-body NIR fluorescence imaging of conjugate 13
accumulation. The drug shows accumulation in the tumor, reaching
peak concentration specifically in the tumor from day 2 post
injection.
Example 44. Biodistribution and Pharmacokinetics of Conjugate
13
Levels of conjugate 13 in blood, liver, kidney and large
MDAMB-231-RFP tumors were assessed at the indicated time points
after i.v. injection of 15 mg/kg (n=27; FIG. 38A). Conjugate 13
reached peak concentrations in the tumors at eight hours
post-injection (11 .mu.g drug/gr tumor tissue; about 3.0% of the
initial drug dose), while its levels in the normal tissues examined
peaked at less than five minutes post-injection and cleared to
nearly background levels within less than 72 hours. The levels of
13 in the tumor were about two orders of magnitude higher than in
the blood during the 48 to 72 hours post-administration period
(FIG. 38A, insert), about 10-fold higher than in the spleen, heart,
brain, fat and muscle (data not shown), and approximately two-fold
higher than in the kidney, liver, intestines, lung and skin (data
not shown). Conjugate 13 underwent rapid hepatic clearance with a
t.sub.1/2 of about four hours. These results clearly show that 13
and similar agents can be used for selective imaging of tumors.
Example 45. The c(RGDfK) Moiety is Essential for Conjugate 13
Uptake by Tumor
In order to determine whether the RGD moiety is imperative for the
selective uptake of conjugate 13 by the tumor, its time-dependent
accumulation within MDA-MB-231-RFP tumors was compared with that of
the RGD-free compound 25. Quantitative assessment of the compound
fluorescence intensity from tissue extracts was performed showing
no accumulation of 25 in the tumor at any time longer than one hour
post administration (FIG. 38B). No specific tumor fluorescence of
25 was seen even in mice bearing large, necrotic tumors, already at
one hour post i.v. injection.
Similar results were obtained in mice bearing small tumors (data
not shown). These findings clearly indicate that the c(RGDfK)
moiety is imperative to tumor-specific bacteriochlorophyll
derivative accumulation and retention.
Example 46. Association of Bacteriochlorophyll Derivatives to Serum
Albumin (SA) Plays a Role in their Uptake and Prolonged
Accumulation in Tumors
In previous studies (Mazor et al., 2005, Brandis et al., 2005), the
present inventors have demonstrated that the water soluble compound
8 (WST-11) is primarily carried in the circulation through
non-covalent associations with SA. However, such non-covalent
association appears insufficient to drive tumor accumulation and
retention of compounds 8 (Rubinstein et al., 2007) and 25 (FIGS.
38B and 39A-B). On the other hand when 25 was covalently bound to
human serum albumin (HSA), it presented some accumulation and
prolonged retention in the MDA-MB-231-RFP tumor (FIGS. 40B and 40C)
and conjugate 13 covalently bound to HSA appears to clear extremely
slowly, if at all, from the tumor (FIGS. 40A and 40C).
These findings corroborate with the aforementioned finding that
covalent binding or non-covalent association of contrast agents
with SA, significantly enhances their uptake by tumors (Chen et
al., 2009).
All together, the above findings indicate that the enhanced
permeability and retention (EPR) effect may support mobilization of
SA-associating therapeutic and imaging agents into the tumor.
However, interactions with tumor-specific receptors are required
for the prolonged retention and accumulation of these compounds
within the tumor.
Example 47. Conjugation of Photosensitizer to c(RGDfK) does not
Increase its Binding Affinity to SA
Following the findings disclosed in Example 46 above, it may be
suggested that stronger binding of conjugate 13 to SA compared with
RGD-free compound 25 analogue accounts for the increased
accumulation of the former in tumors. Therefore, the association
constants of compounds 8 and 25 and conjugates 13 and 24 were
determined. The derived constants Ka.sub.(HSA) (0.54.+-.0.07;
0.44.+-.0.09; 0.12.+-.0.04; and 0.09.+-.0.04, respectively) were
found to be within the same order of magnitude. In fact, those for
the RGDconjugates were four to six fold lower than the association
constants of their RGD-free analogues, ruling out stronger SA
association as the sole basis for RGD-conjugates retention in the
tumor.
Thus, association to SA appears to be important for the uptake of
bacteriochlorophyll derivatives to tumors but is not enhanced by
the RGD moiety.
##STR00003##
##STR00004##
##STR00005##
APPENDIX
TABLE-US-00006 Compound Number Chemical Name Structure 1
Bacteriochlorophyll a ##STR00006## 2
13.sup.2-OH-Bacteriochlorophyll a ##STR00007## 3
Bacteriopheophorbide a ##STR00008## 4
13.sup.2-OH-Bacteriopheophorbide a ##STR00009## 4a Bacteriopurpurin
18 ##STR00010## 5 Chlorophyll a ##STR00011## 6 Pheophorbide a
##STR00012## 7 Palladium Bacteriopheophorbide a ##STR00013## 8
Palladium 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-(2- sulfoethyl)amide potassium salt
##STR00014## 9 Manganese(III) 13.sup.2-OH- Bacteriopheophorbide a
##STR00015## 10 Palladium 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin-13.sup.1-(2,3 - dihydroxypropyl)amide
potassium salt ##STR00016## 11 Palladium 3.sup.1-oxo-15-
methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1-(2-
sulfoethyl)amide-17.sup.3-(RGD- 4C)amide potassium salt
##STR00017## 12 Manganese(III) 13.sup.2-OH-
Bacteriopheophorbide-17.sup.3- (cycloRGDfK)amide ##STR00018## 13
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(2- sulfoethyl)amide-17.sup.3- (cycloRGDfK)amide potassium
salt ##STR00019## 14 Manganese(III) 3.sup.1-oxo-
15-methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1-(2-
sulfoethyl)amide-17.sup.3- (cycloRGDfK)amide potassium salt
##STR00020## 15 Copper(II) 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-(2- sulfoethyl)amide-17.sup.3-
(cycloRGDfK)amide potassium salt ##STR00021## 16 3.sup.1,3.sup.2-
Didehydrorhodochlorin 13.sup.1-(2- sulfoethyl)amide-17.sup.3-
(cycloRGDfK)amide potassium salt ##STR00022## 17 Manganese(III)
3.sup.1,3.sup.2- Didehydrorhodochlorin 13.sup.1-(2-
sulfoethyl)amide-17.sup.3- (cycloRGDfK)amide potassium salt
##STR00023## 18 Copper(II) 3.sup.1,3.sup.2- Didehydrorhodochlorin
13.sup.1-(2- sulfoethyl)amide-17.sup.3- (cycloRGDfK)amide potassium
salt ##STR00024## 19 Palladium Bacteriopurpurin N-(3-
sulfopropylamino)imide-17.sup.3- (cycloRGDfK)amide potassium salt
##STR00025## 20 Meso-5-(4-cycloRGDfK- benzamido)-10,15,20-tris(4-
carboxypheny)porphine ##STR00026## 21 Copper(II) meso-5-(4-
cycloRGDfK-benzamido)- 10,15,20-tris(4-carboxyphenyl) porphine
##STR00027## 22 Gadolinium(III) meso-5- (4-cycloRGDfK-benzamido)-
10,15,20-tris(4-carboxy phenyl)porphine ##STR00028## 23 Palladium
3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin-13.sup.1-(2,3- dihydroxypropyl)amide-17.sup.3-
(cycloRGDfK)amide ##STR00029## 24 Palladium 3.sup.1-oxo-15-
methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1-(2-
sulfoethyl)amide-17.sup.3- (cycloRGDfK)amide potassium salt
##STR00030## 25 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-(2- sulfoethyl)amide potassium salt
##STR00031## 26 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-(2- sulfoethyl)amide-17.sup.3-
(GRGDSP)amide potassium salt ##STR00032## 27
Bacteriopheophorbide-17.sup.3- (cycloRGDfK)amide ##STR00033## 28
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(3-[(3- aminopropyl)amino]propyl)amide-
17.sup.3-(cycloRGDfK)amide ##STR00034## 29 3.sup.1-oxo-15-
methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1-(2,3-
dihydroxypropyl)amide-17.sup.3- (cycloRGDfK)amide ##STR00035## 30
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(2- morpholino-N-ethyl)amide-17.sup.3- (cycloRGDfK)amide
##STR00036## 31 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-{3-[4-
(3-aminopropyl)-piperazin-1-yl]- propyl}amide-17.sup.3-
(cycloRGDfK)amide ##STR00037## 32 Bacteriopheophorbide-17.sup.3-(2-
cycloRGDK-amido-N- ethyl)amide ##STR00038## 33 Palladium
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(2- sulfoethyl)amide-17.sup.3- (GRGDSPK)amide potassium
salt ##STR00039## 34 Palladium 3.sup.1-oxo-15-
methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1-(2-
sulfoethyl)amide-17.sup.3- [(GRGDSP).sub.4K]amide potassium salt
##STR00040## 35 Palladium 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rliodobacteriochlorin 13.sup.1-(2- sulfoethyl)amide-17.sup.3-
(cycloRGDf-N(Me)K)amide potassium salt ##STR00041## 36 Palladium
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(2- sulfoethyl)-17.sup.3-N-[4-heptanedioic acid
bis-(cycloRGDyK- amido)]amide potassium salt ##STR00042## 37
Palladium 3.sup.1-oxo-15- methoxycarbonyl methyl-
Rhodobacteriochlorin 13.sup.1,17.sup.3- cyclo(2-RGD-amido-N-
ethyl)diamide ##STR00043## 38 3.sup.1-oxo-15-
methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1,17.sup.3-
cyclo(2-RGD-amido-N- ethyl)diamide ##STR00044## 39 Palladium
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1,17.sup.3- cyclo{3-[4-(3-aminopropyl-RGD-
amido)-piperazin-1-yl]- propylidiamide ##STR00045## 40 Palladium
3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(2- sulfoethyl)amide-17.sup.3-[4-(methyl-
5-(6-guanidino-hexanoylamino)- pentanoic acid)]amide potassium salt
##STR00046## 41 Palladium 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-(2-
sulfoethyl)amide-17.sup.3-[7-amido-S3- [[1-(4-guanidino-butyryl)-
piperidine-3-carbonyl]-amino]- heptanoic acid] potassium salt
##STR00047## 42 Palladium 3.sup.1-oxo-15- methoxycarbonylmethyl-
Rhodobacteriochlorin 13.sup.1-(2- sulfoethyl)amide-17.sup.3-
(cycloRADfK)amide potassium salt ##STR00048## 43 3.sup.1-oxo-15-
methoxycarbonylmethyl- Rhodobacteriochlorin 13.sup.1-(3-
DTPA-amido-N-propyl)amide- 17.sup.3-(cycloRGDfK)amide ##STR00049##
44 3.sup.1-oxo-15- methoxycarbonylmethyl- Rhodobacteriochlorin
13.sup.1-(3-Gd- DTP A-amido-N-propyl)amide-
17.sup.3-(cycloRGDfK)amide ##STR00050##
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SEQUENCE LISTINGS
1
815PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresyntheticCYCLO(1)..(5)D-AMINO ACID(4)..(4) 1Arg
Gly Asp Phe Lys1 529PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresyntheticCYCLIC(1)..(9)spontaneous oxidative
formation of disulfide bonds 2Cys Asp Cys Arg Gly Asp Cys Phe Cys1
536PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresyntheticLINEAR(1)..(6) 3Gly Arg Gly Asp Ser Pro1
544PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresyntheticCYCLO(1)..(4) 4Arg Gly Asp
Lys157PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresynthetic 5Gly Arg Gly Asp Ser Pro Lys1
5625PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresynthetic 6Gly Arg Gly Asp Ser Pro Gly Arg Gly Asp
Ser Pro Gly Arg Gly Asp1 5 10 15Ser Pro Gly Arg Gly Asp Ser Pro Lys
20 2575PRTArtificial SequenceINTEGRIN BINDING
MOTIFmisc_featuresyntheticCYCLIC(1)..(5)N-METHYL(4)..(5)D-AMINO
ACID(4)..(4) 7Arg Gly Asp Phe Lys1 585PRTArtificial
SequenceINTEGRIN BINDING
MOTIFmisc_featuresyntheticCYCLIC(1)..(5)D-AMINO ACID(4)..(4) 8Arg
Gly Asp Tyr Lys1 5
* * * * *